diff --git a/docs/api/openapi.yaml b/docs/api/openapi.yaml
index 3f1f82806..b73a874a5 100644
--- a/docs/api/openapi.yaml
+++ b/docs/api/openapi.yaml
@@ -20693,8 +20693,8 @@ paths:
         - Environment
       summary: Set the coarse home location
       description: >-
-        Stores the picked city and stamps the effective-from instant. Coordinates are rounded to 2 dp server-side
-        regardless of what was sent.
+        Stores the picked city and stamps the effective-from instant. Coordinates are rounded to 1 decimal (about 11 km)
+        server-side regardless of what was sent.
 
 
         Re-stamping is the part worth knowing: EVERY write moves `since` to now, including one that changes only the
@@ -20850,7 +20850,7 @@ paths:
       summary: Add a travel override
       description: >-
         Declares that the account was somewhere other than home for an inclusive date range; the days it covers resolve
-        against this location instead. Coordinates are rounded to 2 dp server-side.
+        against this location instead. Coordinates are rounded to 1 decimal (about 11 km) server-side.
 
 
         Adding one enqueues a refresh over exactly the declared window so its days re-resolve. Nothing checks for
@@ -72713,10 +72713,10 @@ components:
       properties:
         lat:
           type: number
-          description: Coarse latitude, rounded to 2 dp (~1 km).
+          description: Coarse latitude, rounded to 1 decimal (about 11 km).
         lon:
           type: number
-          description: Coarse longitude, rounded to 2 dp.
+          description: Coarse longitude, rounded to 1 decimal.
         label:
           anyOf:
             - type: string
@@ -72855,10 +72855,10 @@ components:
       properties:
         lat:
           type: number
-          description: Coarse latitude, rounded to 2 dp.
+          description: Coarse latitude, rounded to 1 decimal.
         lon:
           type: number
-          description: Coarse longitude, rounded to 2 dp.
+          description: Coarse longitude, rounded to 1 decimal.
         label:
           type: string
           description: Assembled from name, region and country, e.g. "City, Region, Country".
diff --git a/prisma/migrations/0361_encrypt_route_geometry_and_practitioner_contact/migration.sql b/prisma/migrations/0361_encrypt_route_geometry_and_practitioner_contact/migration.sql
index cd9f3ebf4..a7b97295e 100644
--- a/prisma/migrations/0361_encrypt_route_geometry_and_practitioner_contact/migration.sql
+++ b/prisma/migrations/0361_encrypt_route_geometry_and_practitioner_contact/migration.sql
@@ -12,9 +12,11 @@
 -- columns until the backfill has reached a row. The old columns are dropped in
 -- a later release, once the backfill reports nothing left on every instance.
 --
--- Additive only: no table rewrite, no data change. The geometry loses its NOT
--- NULL because every new track is written to the ciphertext column and the
--- readable one stays empty.
+-- The encryption half is additive: no table rewrite, no data change. The
+-- geometry loses its NOT NULL because every new track is written to the
+-- ciphertext column and the readable one stays empty. The last block below is
+-- the one data change in this file: it coarsens the environment module's
+-- stored coordinates.
 
 ALTER TABLE "workout_routes" ADD COLUMN "geometry_encrypted" BYTEA;
 ALTER TABLE "workout_routes" ALTER COLUMN "geometry" DROP NOT NULL;
@@ -35,3 +37,22 @@ CREATE INDEX IF NOT EXISTS "workout_routes_geometry_backfill_idx"
 CREATE INDEX IF NOT EXISTS "practitioners_contact_backfill_idx"
   ON "practitioners" ("user_id")
   WHERE "phone" IS NOT NULL OR "location" IS NOT NULL;
+
+-- The environment module's stored coordinates drop to 1 decimal, about 11 km
+-- north-south and 7 km east-west at 50° N. They were rounded to 2 decimals
+-- (about 1 km), which places a home in a neighbourhood rather than a town;
+-- the weather reanalysis the module reads is gridded at 9 to 25 km, so the
+-- coarser value costs no accuracy. The app rounds every new write the same
+-- way. Idempotent: rounding an already-rounded value changes nothing.
+UPDATE "users"
+  SET "home_lat" = round("home_lat"::numeric, 1)::double precision,
+      "home_lon" = round("home_lon"::numeric, 1)::double precision
+  WHERE "home_lat" IS NOT NULL OR "home_lon" IS NOT NULL;
+
+UPDATE "environment_travel_locations"
+  SET "lat" = round("lat"::numeric, 1)::double precision,
+      "lon" = round("lon"::numeric, 1)::double precision;
+
+UPDATE "environment_contexts"
+  SET "lat" = round("lat"::numeric, 1)::double precision,
+      "lon" = round("lon"::numeric, 1)::double precision;
diff --git a/prisma/schema.prisma b/prisma/schema.prisma
index ec8d93d28..963b5ce71 100644
--- a/prisma/schema.prisma
+++ b/prisma/schema.prisma
@@ -81,10 +81,13 @@ model User {
   timezone    String    @default("Europe/Berlin")
 
   // v1.25 (W-ENV) — opt-in environmental-context module home location. A coarse,
-  // user-set city (rounded lat/lon, ~city granularity — never a GPS track) the
-  // nightly weather fetch resolves against when no travel override covers the
-  // day. City-level granularity is the privacy floor: the weather model only
-  // needs ~10–25 km. All nullable — an account without the module enabled (or
+  // user-set city (never a GPS track) the nightly weather fetch resolves
+  // against when no travel override covers the day. Stored rounded to 1
+  // decimal (`roundCoarse`): about 11 km north-south and 7 km east-west at
+  // 50° N, a town or a city district. That is the privacy floor, and the
+  // weather reanalysis is gridded at 9 to 25 km, so nothing finer is needed.
+  // Up to v1.39.3 the rounding was 2 decimals (about 1 km, a neighbourhood);
+  // migration 0361 rounded the existing rows. All nullable — an account without the module enabled (or
   // without a home set) simply has no environment rows. `homeTimezone` anchors
   // the day-key an observation is stored under (it can differ from the display
   // `timezone` above for an account that tracks weather for another locale).
@@ -1055,8 +1058,8 @@ model EnvironmentContext {
   /// YYYY-MM-DD anchored to the resolved location's timezone.
   date String
 
-  /// Coarse resolved location for the day (rounded lat/lon + label + the source
-  /// that won precedence).
+  /// Coarse resolved location for the day (lat/lon rounded to 1 decimal, about
+  /// 11 km, + label + the source that won precedence).
   lat           Float
   lon           Float
   /// @internal: human-readable label of the resolved location, stored as
diff --git a/src/app/api/environment/home/route.ts b/src/app/api/environment/home/route.ts
index ded1c12e5..507cfc6bb 100644
--- a/src/app/api/environment/home/route.ts
+++ b/src/app/api/environment/home/route.ts
@@ -2,8 +2,8 @@
  * `PUT /api/environment/home` — set the account's coarse home location.
  *
  * The picked city (rounded lat/lon + label + IANA timezone) is stored on the
- * user. Coordinates are rounded to ~city granularity here as a defence-in-depth
- * floor even if a client sends finer values. Setting a home enqueues a
+ * user. Coordinates are rounded to 1 decimal (about 11 km) here as a
+ * defence-in-depth floor even if a client sends finer values. Setting a home enqueues a
  * lookback fetch so weather appears without waiting for the nightly tick.
  * Module-gated; `userId` is narrowed from auth.
  */
diff --git a/src/app/api/environment/travel/route.ts b/src/app/api/environment/travel/route.ts
index 6f5d31f6c..5f0a0eed2 100644
--- a/src/app/api/environment/travel/route.ts
+++ b/src/app/api/environment/travel/route.ts
@@ -3,7 +3,7 @@
  *
  * For any day in [startDate, endDate] the weather fetch resolves against this
  * coarse location instead of home (a declared trip dominates the home
- * fallback). Coordinates are rounded to ~city granularity. Adding an override
+ * fallback). Coordinates are rounded to 1 decimal (about 11 km). Adding an override
  * enqueues a lookback refresh so its days re-resolve. Module-gated; `userId` is
  * narrowed from auth.
  */
diff --git a/src/lib/environment/__tests__/coarse-location.test.ts b/src/lib/environment/__tests__/coarse-location.test.ts
new file mode 100644
index 000000000..8162e858e
--- /dev/null
+++ b/src/lib/environment/__tests__/coarse-location.test.ts
@@ -0,0 +1,51 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+
+/**
+ * v1.39.4 — the environment module stores coordinates at 1 decimal (about
+ * 11 km), not 2 (about 1 km). The geocoder is where a picked city's
+ * coordinates enter, so its results must already be coarse.
+ */
+beforeEach(() => {
+  vi.resetModules();
+});
+
+afterEach(() => {
+  vi.unstubAllEnvs();
+  vi.unstubAllGlobals();
+});
+
+describe("coarse location", () => {
+  it("rounds a coordinate to one decimal", async () => {
+    const { roundCoarse } = await import("../open-meteo");
+    expect(roundCoarse(52.5163)).toBe(52.5);
+    expect(roundCoarse(13.3777)).toBe(13.4);
+    expect(roundCoarse(-33.8688)).toBe(-33.9);
+    // Already coarse values pass through unchanged.
+    expect(roundCoarse(48.1)).toBe(48.1);
+  });
+
+  it("hands back geocoding results at one decimal", async () => {
+    vi.stubGlobal(
+      "fetch",
+      vi.fn().mockResolvedValue(
+        Response.json(
+          {
+            results: [
+              {
+                name: "Berlin",
+                latitude: 52.52437,
+                longitude: 13.41053,
+                country: "Germany",
+                timezone: "Europe/Berlin",
+              },
+            ],
+          },
+          { status: 200 },
+        ),
+      ),
+    );
+    const { geocodeLocation } = await import("../open-meteo");
+    const [hit] = await geocodeLocation("Berlin");
+    expect(hit).toMatchObject({ lat: 52.5, lon: 13.4 });
+  });
+});
diff --git a/src/lib/environment/open-meteo.ts b/src/lib/environment/open-meteo.ts
index 38e947677..130d44232 100644
--- a/src/lib/environment/open-meteo.ts
+++ b/src/lib/environment/open-meteo.ts
@@ -40,7 +40,7 @@ export const OPEN_METEO_ATTRIBUTION = "Weather data by Open-Meteo.com";
 
 /** One geocoding match — coarse city placement for the home-location picker. */
 export interface GeocodeResult {
-  /** Rounded coarse latitude (2 dp — ~1 km, the privacy floor). */
+  /** Rounded coarse latitude (1 dp, about 11 km, the privacy floor). */
   lat: number;
   /** Rounded coarse longitude (2 dp). */
   lon: number;
@@ -68,9 +68,16 @@ export interface DailyEnvironmentObservation {
   weatherCode: number | null;
 }
 
-/** Round a coordinate to 2 decimals (~1 km) — the coarse-location privacy floor. */
+/**
+ * Round a coordinate to 1 decimal, the coarse-location privacy floor: about
+ * 11 km north-south and 7 km east-west at 50° N, the size of a town or a
+ * city district rather than a street. The weather reanalysis behind the
+ * archive is gridded at 9 to 25 km, so a finer value buys no better weather.
+ * Every stored coordinate of this module goes through here (v1.39.4; it was
+ * 2 decimals, about 1 km, before).
+ */
 export function roundCoarse(value: number): number {
-  return Math.round(value * 100) / 100;
+  return Math.round(value * 10) / 10;
 }
 
 function firstNumber(value: unknown): number | null {
diff --git a/src/lib/environment/service.ts b/src/lib/environment/service.ts
index d1f168127..3c2fb43ed 100644
--- a/src/lib/environment/service.ts
+++ b/src/lib/environment/service.ts
@@ -24,6 +24,7 @@
 import { prisma } from "@/lib/db";
 import {
   fetchDailyEnvironment,
+  roundCoarse,
   type DailyEnvironmentObservation,
 } from "@/lib/environment/open-meteo";
 import type { EnvironmentLocationSource } from "@/generated/prisma/client";
@@ -256,8 +257,10 @@ function buildUpsert(
   obs: DailyEnvironmentObservation,
 ) {
   const data = {
-    lat: loc.lat,
-    lon: loc.lon,
+    // Already coarse at the source; rounded again so a per-day row never holds
+    // more precision than the privacy floor, whatever resolved it.
+    lat: roundCoarse(loc.lat),
+    lon: roundCoarse(loc.lon),
     locationLabel: loc.label,
     source: loc.source,
     tempMin: obs.tempMin,
diff --git a/src/lib/export/environment-backup.ts b/src/lib/export/environment-backup.ts
index c02042875..cc96d9853 100644
--- a/src/lib/export/environment-backup.ts
+++ b/src/lib/export/environment-backup.ts
@@ -60,6 +60,7 @@
  */
 import type { Prisma, PrismaClient } from "@/generated/prisma/client";
 import type { EnvironmentLocationSource } from "@/generated/prisma/client";
+import { roundCoarse } from "@/lib/environment/open-meteo";
 
 /** One day's environmental observation, at the location resolved for that day. */
 export interface EnvironmentContextBackupEntry {
@@ -312,8 +313,10 @@ export async function restoreEnvironmentData(
         // neither bound goes near a `Date`.
         startDate: entry.startDate,
         endDate: entry.endDate,
-        lat: entry.lat,
-        lon: entry.lon,
+        // A file written before v1.39.4 carries 2-decimal coordinates; they
+        // come back at today's privacy floor.
+        lat: roundCoarse(entry.lat),
+        lon: roundCoarse(entry.lon),
         label: entry.label,
         ...(entry.createdAt ? { createdAt: new Date(entry.createdAt) } : {}),
         ...(entry.updatedAt ? { updatedAt: new Date(entry.updatedAt) } : {}),
@@ -326,8 +329,8 @@ export async function restoreEnvironmentData(
       data: payload.environmentContexts.map((entry) => ({
         userId: ownerId,
         date: entry.date,
-        lat: entry.lat,
-        lon: entry.lon,
+        lat: roundCoarse(entry.lat),
+        lon: roundCoarse(entry.lon),
         locationLabel: entry.locationLabel,
         source: entry.source,
         tempMin: entry.tempMin ?? null,
diff --git a/src/lib/openapi/routes/environment.ts b/src/lib/openapi/routes/environment.ts
index 8d4c132ab..40339d20c 100644
--- a/src/lib/openapi/routes/environment.ts
+++ b/src/lib/openapi/routes/environment.ts
@@ -11,7 +11,7 @@
  * the `environment` module off, every one of the six paths answers 403
  * `module.disabled` before it does anything else.
  *
- * Coordinates are rounded to ~city granularity (2 dp) on the way in, as a
+ * Coordinates are rounded to 1 decimal (about 11 km) on the way in, as a
  * floor under whatever precision a client sends. That rounding is why the
  * geocode results and the stored home read back coarser than they were
  * picked.
@@ -58,8 +58,10 @@ const geocodeQuery = geocodeQuerySchema.meta({
 
 const environmentHome = z
   .object({
-    lat: z.number().describe("Coarse latitude, rounded to 2 dp (~1 km)."),
-    lon: z.number().describe("Coarse longitude, rounded to 2 dp."),
+    lat: z
+      .number()
+      .describe("Coarse latitude, rounded to 1 decimal (about 11 km)."),
+    lon: z.number().describe("Coarse longitude, rounded to 1 decimal."),
     label: z.string().nullable(),
     timezone: z
       .string()
@@ -142,8 +144,8 @@ const environmentOverview = z
 
 const geocodeResult = z
   .object({
-    lat: z.number().describe("Coarse latitude, rounded to 2 dp."),
-    lon: z.number().describe("Coarse longitude, rounded to 2 dp."),
+    lat: z.number().describe("Coarse latitude, rounded to 1 decimal."),
+    lon: z.number().describe("Coarse longitude, rounded to 1 decimal."),
     label: z
       .string()
       .describe(
@@ -186,7 +188,7 @@ export const environmentPaths: NonNullable<ZodOpenApiObject["paths"]> = {
       tags: ["Environment"],
       summary: "Set the coarse home location",
       description:
-        "Stores the picked city and stamps the effective-from instant. Coordinates are rounded to 2 dp server-side regardless of what was sent.\n\nRe-stamping is the part worth knowing: EVERY write moves `since` to now, including one that changes only the label. Days before the new `since` stop resolving against this home, so a correction to an existing home un-attributes the history that home used to cover.\n\nOn success a lookback fetch is enqueued so recent days populate without waiting for the nightly tick. That enqueue is best-effort — it no-ops cleanly when no worker is bound and the response is a 200 either way.\n\nBody cap 4 KiB. Module-gated.",
+        "Stores the picked city and stamps the effective-from instant. Coordinates are rounded to 1 decimal (about 11 km) server-side regardless of what was sent.\n\nRe-stamping is the part worth knowing: EVERY write moves `since` to now, including one that changes only the label. Days before the new `since` stop resolving against this home, so a correction to an existing home un-attributes the history that home used to cover.\n\nOn success a lookback fetch is enqueued so recent days populate without waiting for the nightly tick. That enqueue is best-effort — it no-ops cleanly when no worker is bound and the response is a 200 either way.\n\nBody cap 4 KiB. Module-gated.",
       requestBody: {
         required: true,
         content: { "application/json": { schema: homeLocationRequest } },
@@ -309,7 +311,7 @@ export const environmentPaths: NonNullable<ZodOpenApiObject["paths"]> = {
       tags: ["Environment"],
       summary: "Add a travel override",
       description:
-        "Declares that the account was somewhere other than home for an inclusive date range; the days it covers resolve against this location instead. Coordinates are rounded to 2 dp server-side.\n\nAdding one enqueues a refresh over exactly the declared window so its days re-resolve. Nothing checks for overlap with an existing override — two ranges covering the same day are accepted, and the worker picks between them.\n\nBody cap 4 KiB. Module-gated.",
+        "Declares that the account was somewhere other than home for an inclusive date range; the days it covers resolve against this location instead. Coordinates are rounded to 1 decimal (about 11 km) server-side.\n\nAdding one enqueues a refresh over exactly the declared window so its days re-resolve. Nothing checks for overlap with an existing override — two ranges covering the same day are accepted, and the worker picks between them.\n\nBody cap 4 KiB. Module-gated.",
       requestBody: {
         required: true,
         content: { "application/json": { schema: travelLocationRequest } },
diff --git a/tests/integration/backup-round-trip.test.ts b/tests/integration/backup-round-trip.test.ts
index 6f4cc1117..a9cae4e6b 100644
--- a/tests/integration/backup-round-trip.test.ts
+++ b/tests/integration/backup-round-trip.test.ts
@@ -1206,14 +1206,16 @@ async function seedEveryTwoEndedModel(prisma: PrismaClient): Promise<void> {
   // coordinates and different weather, and the trip day's reading only makes
   // sense next to the period that explains it: with the period gone, the next
   // refresh re-resolves 2026-06-15 to Berlin and upserts Berlin's weather over
-  // it. The assertion after the restore reads the two back TOGETHER.
+  // it. The assertion after the restore reads the two back TOGETHER. The
+  // coordinates are at 1 decimal, the precision the app stores since v1.39.4;
+  // a restore rounds anything finer, so finer values would not round-trip.
   await prisma.environmentTravelLocation.create({
     data: {
       userId: OWNER_ID,
       startDate: "2026-06-10",
       endDate: "2026-06-20",
-      lat: 41.3874,
-      lon: 2.1686,
+      lat: 41.4,
+      lon: 2.2,
       label: "Barcelona",
     },
   });
@@ -1222,8 +1224,8 @@ async function seedEveryTwoEndedModel(prisma: PrismaClient): Promise<void> {
       {
         userId: OWNER_ID,
         date: "2026-06-15",
-        lat: 41.3874,
-        lon: 2.1686,
+        lat: 41.4,
+        lon: 2.2,
         locationLabel: "Barcelona",
         source: "TRAVEL",
         tempMin: 19.4,
@@ -1243,8 +1245,8 @@ async function seedEveryTwoEndedModel(prisma: PrismaClient): Promise<void> {
       {
         userId: OWNER_ID,
         date: "2026-07-01",
-        lat: 52.52,
-        lon: 13.405,
+        lat: 52.5,
+        lon: 13.4,
         locationLabel: "Berlin",
         source: "HOME",
         tempMin: 13.1,
@@ -2394,8 +2396,8 @@ describe("every model the plan claims two-ended survives a real restore", () =>
     ).toEqual([
       {
         date: "2026-06-15",
-        lat: 41.3874,
-        lon: 2.1686,
+        lat: 41.4,
+        lon: 2.2,
         locationLabel: "Barcelona",
         source: "TRAVEL",
         tempMean: 23.6,
@@ -2406,8 +2408,8 @@ describe("every model the plan claims two-ended survives a real restore", () =>
       },
       {
         date: "2026-07-01",
-        lat: 52.52,
-        lon: 13.405,
+        lat: 52.5,
+        lon: 13.4,
         locationLabel: "Berlin",
         source: "HOME",
         tempMean: 17.9,
diff --git a/tests/integration/environment-coarse-location.test.ts b/tests/integration/environment-coarse-location.test.ts
new file mode 100644
index 000000000..45ee987ea
--- /dev/null
+++ b/tests/integration/environment-coarse-location.test.ts
@@ -0,0 +1,209 @@
+/**
+ * v1.39.4 — the environment module's coordinates are stored at 1 decimal
+ * (about 11 km), against real Postgres.
+ *
+ *   - setting a home and adding a travel period store the coarse value, and
+ *     the home answer carries it in the same shape as before (numbers);
+ *   - a restore of a file written with 2-decimal coordinates stores them
+ *     coarse;
+ *   - the rounding block of migration 0361 coarsens rows written before it,
+ *     and running it twice changes nothing more.
+ */
+import { readFileSync } from "node:fs";
+import { join } from "node:path";
+import { beforeEach, describe, expect, it, vi } from "vitest";
+
+process.env.ENCRYPTION_KEY ??=
+  "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef";
+
+import { PUT as putHome } from "@/app/api/environment/home/route";
+import { POST as postTravel } from "@/app/api/environment/travel/route";
+import { restoreEnvironmentData } from "@/lib/export/environment-backup";
+
+import { cookieJar, headerJar } from "./mock-next-headers";
+import { getPrismaClient, truncateAllTables } from "./setup";
+
+vi.mock("next/headers", async () => {
+  const { cookieJar, headerJar } = await import("./mock-next-headers");
+  return {
+    headers: vi.fn(async () => ({
+      get: (name: string) => headerJar.get(name.toLowerCase()) ?? null,
+    })),
+    cookies: vi.fn(async () => ({
+      get: (name: string) => {
+        const value = cookieJar.get(name);
+        return value ? { name, value } : undefined;
+      },
+      set: (name: string, value: string) => cookieJar.set(name, value),
+      delete: (name: string) => cookieJar.delete(name),
+    })),
+  };
+});
+
+vi.mock("@/lib/db-compat", () => ({
+  ensureDbCompatibility: vi.fn().mockResolvedValue(undefined),
+}));
+
+const OWNER_ID = "environment-coarse-owner";
+
+function jsonRequest(url: string, method: string, body: unknown) {
+  return new Request(url, {
+    method,
+    headers: { "content-type": "application/json" },
+    body: JSON.stringify(body),
+  }) as never;
+}
+
+beforeEach(async () => {
+  const prisma = getPrismaClient();
+  await truncateAllTables(prisma);
+  cookieJar.clear();
+  headerJar.clear();
+  await prisma.user.create({
+    data: {
+      id: OWNER_ID,
+      username: OWNER_ID,
+      email: `${OWNER_ID}@example.test`,
+      timezone: "Europe/Berlin",
+    },
+  });
+  const session = await prisma.session.create({
+    data: {
+      userId: OWNER_ID,
+      expiresAt: new Date(Date.now() + 7 * 24 * 60 * 60 * 1000),
+      mfaVerifiedAt: new Date(),
+    },
+  });
+  cookieJar.set("healthlog_session", session.id);
+});
+
+describe("environment coordinates at one decimal", () => {
+  it("stores a home and a travel period coarse, and answers in the same shape", async () => {
+    const home = await putHome(
+      jsonRequest("http://localhost/api/environment/home", "PUT", {
+        lat: 52.5163,
+        lon: 13.3777,
+        label: "Berlin, Germany",
+        timezone: "Europe/Berlin",
+      }),
+    );
+    expect(home.status).toBe(200);
+    expect((await home.json()).data.home).toMatchObject({
+      lat: 52.5,
+      lon: 13.4,
+    });
+    const user = await getPrismaClient().user.findUniqueOrThrow({
+      where: { id: OWNER_ID },
+    });
+    expect([user.homeLat, user.homeLon]).toEqual([52.5, 13.4]);
+
+    const travel = await postTravel(
+      jsonRequest("http://localhost/api/environment/travel", "POST", {
+        startDate: "2026-08-01",
+        endDate: "2026-08-10",
+        lat: 48.13743,
+        lon: 11.57549,
+        label: "Munich, Germany",
+      }),
+    );
+    expect(travel.status).toBe(201);
+    const stored = await getPrismaClient().environmentTravelLocation.findMany({
+      where: { userId: OWNER_ID },
+    });
+    expect(stored.map((t) => [t.lat, t.lon])).toEqual([[48.1, 11.6]]);
+  });
+
+  it("restores a file written with two-decimal coordinates at one decimal", async () => {
+    const prisma = getPrismaClient();
+    await prisma.$transaction((tx) =>
+      restoreEnvironmentData(tx, OWNER_ID, {
+        environmentTravelLocations: [
+          {
+            startDate: "2026-08-01",
+            endDate: "2026-08-10",
+            lat: 48.14,
+            lon: 11.58,
+            label: "Munich, Germany",
+          },
+        ],
+        environmentContexts: [
+          {
+            date: "2026-08-02",
+            lat: 48.14,
+            lon: 11.58,
+            locationLabel: "Munich, Germany",
+            source: "TRAVEL",
+          },
+        ],
+      }),
+    );
+    const travel = await prisma.environmentTravelLocation.findMany({
+      where: { userId: OWNER_ID },
+    });
+    const days = await prisma.environmentContext.findMany({
+      where: { userId: OWNER_ID },
+    });
+    expect(travel.map((t) => [t.lat, t.lon])).toEqual([[48.1, 11.6]]);
+    expect(days.map((d) => [d.lat, d.lon])).toEqual([[48.1, 11.6]]);
+  });
+
+  it("coarsens rows written before migration 0361, idempotently", async () => {
+    const prisma = getPrismaClient();
+    await prisma.user.update({
+      where: { id: OWNER_ID },
+      data: { homeLat: 52.52, homeLon: 13.38 },
+    });
+    await prisma.environmentTravelLocation.create({
+      data: {
+        userId: OWNER_ID,
+        startDate: "2026-08-01",
+        endDate: "2026-08-10",
+        lat: 48.14,
+        lon: 11.58,
+        label: "Munich, Germany",
+      },
+    });
+    await prisma.environmentContext.create({
+      data: {
+        userId: OWNER_ID,
+        date: "2026-08-02",
+        lat: -33.87,
+        lon: 151.21,
+        locationLabel: "Sydney, Australia",
+        source: "TRAVEL",
+      },
+    });
+
+    const sql = readFileSync(
+      join(
+        __dirname,
+        "../../prisma/migrations/0361_encrypt_route_geometry_and_practitioner_contact/migration.sql",
+      ),
+      "utf8",
+    );
+    const statements = sql
+      .slice(sql.indexOf('UPDATE "users"'))
+      .split(";")
+      .map((s) => s.trim())
+      .filter((s) => s.length > 0);
+    expect(statements).toHaveLength(3);
+
+    for (let pass = 0; pass < 2; pass++) {
+      for (const statement of statements) {
+        await prisma.$executeRawUnsafe(statement);
+      }
+      const user = await prisma.user.findUniqueOrThrow({
+        where: { id: OWNER_ID },
+      });
+      expect([user.homeLat, user.homeLon]).toEqual([52.5, 13.4]);
+      const travel = await prisma.environmentTravelLocation.findFirstOrThrow({
+        where: { userId: OWNER_ID },
+      });
+      expect([travel.lat, travel.lon]).toEqual([48.1, 11.6]);
+      const day = await prisma.environmentContext.findFirstOrThrow({
+        where: { userId: OWNER_ID },
+      });
+      expect([day.lat, day.lon]).toEqual([-33.9, 151.2]);
+    }
+  });
+});