diff --git a/docs/api/openapi.yaml b/docs/api/openapi.yaml
index d4a229650..6033f1998 100644
--- a/docs/api/openapi.yaml
+++ b/docs/api/openapi.yaml
@@ -60433,6 +60433,14 @@ components:
                 enum:
                   - above
                   - below
+              basis:
+                type: string
+                enum:
+                  - day
+                  - sameHours
+                description: "What `low`/`high` describe: the usual whole day (`day`), or the usual range for this time of day
+                  (`sameHours`), used for a day still in progress whose mean moves with the hour (glucose). Additive
+                  since v1.40.3."
             required:
               - type
               - value
@@ -60440,6 +60448,7 @@ components:
               - low
               - high
               - direction
+              - basis
             additionalProperties: false
         shifts:
           type: array
diff --git a/messages/de.json b/messages/de.json
index 94c4d89c1..c45a8287b 100644
--- a/messages/de.json
+++ b/messages/de.json
@@ -4492,6 +4492,7 @@
       "shiftUp": "{vital} hat sich gegenüber deiner jüngsten Norm nach oben verschoben.",
       "shiftDown": "{vital} hat sich gegenüber deiner jüngsten Norm nach unten verschoben.",
       "rangeContext": "Aktuell {value}, sonst {low}–{high}.",
+      "rangeContextTimeOfDay": "Aktuell {value}, zu dieser Tageszeit sonst {low}–{high}.",
       "shiftContext": "Etwa {before} davor, {after} seitdem."
     },
     "breathingScreening": {
@@ -11018,6 +11019,7 @@
       "steadyWeeksOther": "Seit {count} Wochen stabil",
       "valueWithUnit": "{value} {unit}",
       "rangeWithUnit": "{low} bis {high} {unit}",
+      "rangeAtThisTime": "{range} für diese Tageszeit",
       "vital": {
         "RESTING_HEART_RATE": "Ruhepuls",
         "HEART_RATE_VARIABILITY": "Herzfrequenzvariabilität",
diff --git a/messages/en.json b/messages/en.json
index 92aff03a8..6582a631e 100644
--- a/messages/en.json
+++ b/messages/en.json
@@ -4492,6 +4492,7 @@
       "shiftUp": "{vital} has shifted up from your recent normal.",
       "shiftDown": "{vital} has shifted down from your recent normal.",
       "rangeContext": "Now {value}, usually {low}–{high}.",
+      "rangeContextTimeOfDay": "Now {value}, usually {low}–{high} at this time of day.",
       "shiftContext": "Around {before} before, {after} since."
     },
     "breathingScreening": {
@@ -11018,6 +11019,7 @@
       "steadyWeeksOther": "Steady for {count} weeks",
       "valueWithUnit": "{value} {unit}",
       "rangeWithUnit": "{low} to {high} {unit}",
+      "rangeAtThisTime": "{range} for this time of day",
       "vital": {
         "RESTING_HEART_RATE": "Resting heart rate",
         "HEART_RATE_VARIABILITY": "Heart-rate variability",
diff --git a/messages/es.json b/messages/es.json
index 9f21ada5b..d4996861e 100644
--- a/messages/es.json
+++ b/messages/es.json
@@ -4492,6 +4492,7 @@
       "shiftUp": "{vital} ha subido respecto a tu normal reciente.",
       "shiftDown": "{vital} ha bajado respecto a tu normal reciente.",
       "rangeContext": "Ahora {value}, normalmente {low}–{high}.",
+      "rangeContextTimeOfDay": "Ahora {value}, normalmente {low}–{high} a esta hora del día.",
       "shiftContext": "Cerca de {before} antes, {after} desde entonces."
     },
     "breathingScreening": {
@@ -11018,6 +11019,7 @@
       "steadyWeeksOther": "Estable desde hace {count} semanas",
       "valueWithUnit": "{value} {unit}",
       "rangeWithUnit": "{low} a {high} {unit}",
+      "rangeAtThisTime": "{range} para esta hora del día",
       "vital": {
         "RESTING_HEART_RATE": "Frecuencia cardíaca en reposo",
         "HEART_RATE_VARIABILITY": "Variabilidad de la frecuencia cardíaca",
diff --git a/messages/fr.json b/messages/fr.json
index 3bc9a18f4..8b11b0e67 100644
--- a/messages/fr.json
+++ b/messages/fr.json
@@ -4492,6 +4492,7 @@
       "shiftUp": "{vital} a augmenté par rapport à votre normale récente.",
       "shiftDown": "{vital} a diminué par rapport à votre normale récente.",
       "rangeContext": "Actuellement {value}, habituellement {low}–{high}.",
+      "rangeContextTimeOfDay": "Actuellement {value}, habituellement {low}–{high} à ce moment de la journée.",
       "shiftContext": "Environ {before} avant, {after} depuis."
     },
     "breathingScreening": {
@@ -11018,6 +11019,7 @@
       "steadyWeeksOther": "Stable depuis {count} semaines",
       "valueWithUnit": "{value} {unit}",
       "rangeWithUnit": "{low} à {high} {unit}",
+      "rangeAtThisTime": "{range} pour ce moment de la journée",
       "vital": {
         "RESTING_HEART_RATE": "Fréquence cardiaque au repos",
         "HEART_RATE_VARIABILITY": "Variabilité de la fréquence cardiaque",
diff --git a/messages/it.json b/messages/it.json
index ae8c7982b..03b89d1a8 100644
--- a/messages/it.json
+++ b/messages/it.json
@@ -4492,6 +4492,7 @@
       "shiftUp": "{vital} si è spostato verso l'alto rispetto alla tua norma recente.",
       "shiftDown": "{vital} si è spostato verso il basso rispetto alla tua norma recente.",
       "rangeContext": "Ora {value}, di solito {low}–{high}.",
+      "rangeContextTimeOfDay": "Ora {value}, di solito {low}–{high} a quest'ora del giorno.",
       "shiftContext": "Circa {before} prima, {after} da allora."
     },
     "breathingScreening": {
@@ -11018,6 +11019,7 @@
       "steadyWeeksOther": "Stabile da {count} settimane",
       "valueWithUnit": "{value} {unit}",
       "rangeWithUnit": "da {low} a {high} {unit}",
+      "rangeAtThisTime": "{range} per quest'ora del giorno",
       "vital": {
         "RESTING_HEART_RATE": "Frequenza cardiaca a riposo",
         "HEART_RATE_VARIABILITY": "Variabilità della frequenza cardiaca",
diff --git a/messages/ko.json b/messages/ko.json
index 80d038191..9ba7aa1be 100644
--- a/messages/ko.json
+++ b/messages/ko.json
@@ -4492,6 +4492,7 @@
       "shiftUp": "{vital} — 최근 평소 수준보다 올라갔어요.",
       "shiftDown": "{vital} — 최근 평소 수준보다 내려갔어요.",
       "rangeContext": "지금 {value}, 평소 {low}–{high}.",
+      "rangeContextTimeOfDay": "지금 {value}, 이 시간대 평소 {low}–{high}.",
       "shiftContext": "이전엔 약 {before}, 이후엔 {after}."
     },
     "breathingScreening": {
@@ -11018,6 +11019,7 @@
       "steadyWeeksOther": "{count}주째 안정적",
       "valueWithUnit": "{value} {unit}",
       "rangeWithUnit": "{low}~{high} {unit}",
+      "rangeAtThisTime": "이 시간대 기준 {range}",
       "vital": {
         "RESTING_HEART_RATE": "안정 시 심박수",
         "HEART_RATE_VARIABILITY": "심박 변이도",
diff --git a/messages/pl.json b/messages/pl.json
index 809bc6c8e..3cca6e11c 100644
--- a/messages/pl.json
+++ b/messages/pl.json
@@ -4492,6 +4492,7 @@
       "shiftUp": "{vital} przesunął się w górę względem Twojej ostatniej normy.",
       "shiftDown": "{vital} przesunął się w dół względem Twojej ostatniej normy.",
       "rangeContext": "Teraz {value}, zwykle {low}–{high}.",
+      "rangeContextTimeOfDay": "Teraz {value}, zwykle {low}–{high} o tej porze dnia.",
       "shiftContext": "Około {before} wcześniej, {after} od tego czasu."
     },
     "breathingScreening": {
@@ -11018,6 +11019,7 @@
       "steadyWeeksOther": "Stabilnie od {count} tygodni",
       "valueWithUnit": "{value} {unit}",
       "rangeWithUnit": "{low} do {high} {unit}",
+      "rangeAtThisTime": "{range} o tej porze dnia",
       "vital": {
         "RESTING_HEART_RATE": "Tętno spoczynkowe",
         "HEART_RATE_VARIABILITY": "Zmienność rytmu serca",
diff --git a/src/components/insights/health-status-card.tsx b/src/components/insights/health-status-card.tsx
index 354843b80..87487f8f1 100644
--- a/src/components/insights/health-status-card.tsx
+++ b/src/components/insights/health-status-card.tsx
@@ -109,11 +109,16 @@ export function HealthStatusCard({
                 )}
               </p>
               <p className="text-muted-foreground text-xs leading-snug">
-                {t("insights.healthStatus.rangeContext", {
-                  value: metricValue(d.type, d.value),
-                  low: metricValue(d.type, d.low),
-                  high: metricValue(d.type, d.high),
-                })}
+                {t(
+                  d.basis === "sameHours"
+                    ? "insights.healthStatus.rangeContextTimeOfDay"
+                    : "insights.healthStatus.rangeContext",
+                  {
+                    value: metricValue(d.type, d.value),
+                    low: metricValue(d.type, d.low),
+                    high: metricValue(d.type, d.high),
+                  },
+                )}
               </p>
             </div>
           </div>
diff --git a/src/lib/daily/__tests__/load-digest.test.ts b/src/lib/daily/__tests__/load-digest.test.ts
index 498cae53f..6544fd576 100644
--- a/src/lib/daily/__tests__/load-digest.test.ts
+++ b/src/lib/daily/__tests__/load-digest.test.ts
@@ -677,6 +677,52 @@ describe("loadDailyDigest — Today overview inputs", () => {
     expect(digest.briefingLead).toBeNull();
   });
 
+  it("says a glucose range is the usual one for this time of day", async () => {
+    // Today's glucose is held against the same hours of earlier days, so the
+    // range it names is not the whole-day band shown elsewhere.
+    const { getServerTranslator: real } = await vi.importActual<
+      typeof import("@/lib/i18n/server-translator")
+    >("@/lib/i18n/server-translator");
+    const { getServerTranslator } =
+      await import("@/lib/i18n/server-translator");
+    vi.mocked(getServerTranslator).mockReturnValueOnce(real("en"));
+    vi.mocked(readDashboardSnapshotCached).mockResolvedValueOnce({
+      ...SNAPSHOT,
+      body: {
+        ...SNAPSHOT.body,
+        briefingAi: aiUnavailable("user_disabled"),
+      },
+    } as never);
+    vi.mocked(aiCapabilityToServe).mockResolvedValue(
+      aiUnavailable("user_disabled"),
+    );
+    vi.mocked(computeCoincidentDeviation).mockResolvedValueOnce({
+      status: "ok",
+      value: {
+        fired: false,
+        contributing: [],
+        day: "2026-07-17",
+        illnessExplained: false,
+        vitals: [
+          {
+            type: "BLOOD_GLUCOSE",
+            value: 70,
+            center: 86,
+            low: 80,
+            high: 92,
+            outside: true,
+            direction: "below",
+            daysAgo: 0,
+            basis: "sameHours",
+          },
+        ],
+      },
+    } as never);
+    const digest = await loadDailyDigest(USER, NOW);
+    expect(digest.lead?.source).toBe("signal");
+    expect(digest.lead?.text).toMatch(/80 to 92 mg\/dL for this time of day/);
+  });
+
   it("publishes how long the score has held", async () => {
     vi.mocked(readDashboardSnapshotCached).mockResolvedValueOnce({
       ...SNAPSHOT,
diff --git a/src/lib/daily/load-digest.ts b/src/lib/daily/load-digest.ts
index 95c609b3a..db39186f9 100644
--- a/src/lib/daily/load-digest.ts
+++ b/src/lib/daily/load-digest.ts
@@ -259,6 +259,8 @@ interface ExtrasVital {
   high: number;
   direction: "above" | "below" | "in";
   daysAgo: number;
+  /** Held against the same hours of earlier days, see `VitalDeviation`. */
+  basis?: "sameHours";
 }
 
 /**
@@ -286,6 +288,7 @@ async function gatherVitals(
       high: v.high,
       direction: v.direction,
       daysAgo: Number.isFinite(v.daysAgo) ? v.daysAgo : Number.MAX_SAFE_INTEGER,
+      ...(v.basis ? { basis: v.basis } : {}),
     }));
   } catch {
     return [];
@@ -370,11 +373,18 @@ function toTodayVital(
       value: shown(vital.value),
       unit,
     }),
-    rangeLabel: t("daily.today.rangeWithUnit", {
-      low: shown(vital.low),
-      high: shown(vital.high),
-      unit,
-    }),
+    rangeLabel: (() => {
+      const range = t("daily.today.rangeWithUnit", {
+        low: shown(vital.low),
+        high: shown(vital.high),
+        unit,
+      });
+      // A range read off the same hours of earlier days is the usual range
+      // for this time of day, not the whole-day band shown elsewhere.
+      return vital.basis === "sameHours"
+        ? t("daily.today.rangeAtThisTime", { range })
+        : range;
+    })(),
     moduleKey: moduleForMeasurementType(vital.type),
   };
 }
diff --git a/src/lib/insights/__tests__/health-status.test.ts b/src/lib/insights/__tests__/health-status.test.ts
index a932d476b..b5ad57d9c 100644
--- a/src/lib/insights/__tests__/health-status.test.ts
+++ b/src/lib/insights/__tests__/health-status.test.ts
@@ -61,4 +61,15 @@ describe("summariseHealthStatus", () => {
     const s = summariseHealthStatus([vital(true, "in")], []);
     expect(s.present).toBe(false);
   });
+
+  it("says when a deviation is measured against the same hours", () => {
+    const s = summariseHealthStatus(
+      [
+        { ...vital(true, "below"), type: "BLOOD_GLUCOSE", basis: "sameHours" },
+        vital(true, "above"),
+      ],
+      [],
+    );
+    expect(s.deviations.map((d) => d.basis)).toEqual(["sameHours", "day"]);
+  });
 });
diff --git a/src/lib/insights/derived/__tests__/coincident-deviation.test.ts b/src/lib/insights/derived/__tests__/coincident-deviation.test.ts
index 60036caaf..5e035a06d 100644
--- a/src/lib/insights/derived/__tests__/coincident-deviation.test.ts
+++ b/src/lib/insights/derived/__tests__/coincident-deviation.test.ts
@@ -282,6 +282,31 @@ describe("glucose — a day in progress is compared with the same hours", () =>
     expect(glucose!.center).toBe(85);
   });
 
+  it("cuts earlier days at today's latest reading, not at the clock", async () => {
+    // 14:00, and today holds only the 07:00 fasting value. Cut at 14:00 the
+    // earlier days include their 13:00 post-meal readings (mean ~122) and the
+    // morning read as low; cut at 07:00 they are fasting too.
+    findMany.mockImplementation(async (args: { where: { type: string } }) => {
+      if (args.where.type === "BLOOD_GLUCOSE") {
+        return [
+          ...glucoseDays(["07:00", "13:00", "19:00"], [85, 160, 150]),
+          { value: 84, measuredAt: new Date("2026-06-02T07:00:00Z") },
+        ];
+      }
+      if (args.where.type === "RESTING_HEART_RATE") return rhrFlat;
+      return [];
+    });
+    const result = await computeCoincidentDeviation("u1", PROFILE, {
+      now: new Date("2026-06-02T14:00:00Z"),
+      tz: "UTC",
+    });
+    if (result.status !== "ok") throw new Error("expected ok");
+    const glucose = result.value.vitals.find((v) => v.type === "BLOOD_GLUCOSE");
+    expect(glucose!.direction).toBe("in");
+    expect(glucose!.center).toBe(85);
+    expect(glucose!.basis).toBe("sameHours");
+  });
+
   it("still flags a morning that is low against earlier mornings", async () => {
     findMany.mockImplementation(async (args: { where: { type: string } }) => {
       if (args.where.type === "BLOOD_GLUCOSE") {
diff --git a/src/lib/insights/derived/coincident-deviation.ts b/src/lib/insights/derived/coincident-deviation.ts
index 0bf494ccd..5588e3616 100644
--- a/src/lib/insights/derived/coincident-deviation.ts
+++ b/src/lib/insights/derived/coincident-deviation.ts
@@ -77,7 +77,8 @@ export const COINCIDENT_MIN_BANDS = 2;
  * fasting mean, and a band built from whole days sits well above it: a
  * perfectly ordinary morning read as "below your range". For these types a
  * day still in progress is compared with the same hours of the earlier days
- * (each day cut at the current local clock time), never with whole days.
+ * (each day cut at the local time of today's latest reading), never with
+ * whole days.
  */
 const SAME_HOURS_TYPES: ReadonlySet<MeasurementType> = new Set([
   "BLOOD_GLUCOSE",
@@ -113,20 +114,26 @@ export function sameHoursStanding(
   };
 }
 
-/** The current local clock time in `tz`, `HH:MM:SS`. */
-function localClockNow(now: Date, tz: string): string {
-  const c = wallClockInTz(now, tz);
+/** The local clock time of an instant in `tz`, `HH:MM:SS`. */
+function localClockOf(at: Date, tz: string): string {
+  const c = wallClockInTz(at, tz);
   const pad = (n: number) => String(n).padStart(2, "0");
   return `${pad(c.hour)}:${pad(c.minute)}:${pad(c.second)}`;
 }
 
-/** Per-day aggregates of the window, each day cut at the current clock. */
+/**
+ * Per-day aggregates of the window, each day cut at the local clock time of
+ * today's latest reading. Not at `now`: at two in the afternoon a day whose
+ * only reading is the 07:00 fasting value would otherwise be held against
+ * earlier days that include their lunch.
+ */
 async function readSameHoursDays(
   userId: string,
   type: MeasurementType,
   windowDays: number,
   now: Date,
   tz: string,
+  cutAt: Date,
 ) {
   return readDayAggregates({
     userId,
@@ -135,7 +142,7 @@ async function readSameHoursDays(
     until: now,
     timeZone: tz,
     valueRange: plausibleMetricRange(type),
-    upToLocalTime: localClockNow(now, tz),
+    upToLocalTime: localClockOf(cutAt, tz),
   });
 }
 
@@ -162,6 +169,14 @@ export interface VitalDeviation {
    * `contributing` below already does.
    */
   daysAgo: number;
+  /**
+   * `"sameHours"` when today's value was held against the same hours of the
+   * earlier days rather than their whole-day band (a day still in progress
+   * for a type whose day mean moves with the hour, see `SAME_HOURS_TYPES`).
+   * `low` / `high` are then the usual range for this time of day, and a
+   * surface naming them says so. Absent for the whole-day comparison.
+   */
+  basis?: "sameHours";
 }
 
 export interface CoincidentDeviationValue {
@@ -195,6 +210,7 @@ export function classifyDeviation(
   high: number,
   center: number,
   daysAgo: number = 0,
+  basis?: "sameHours",
 ): VitalDeviation {
   const above = value > high;
   const below = value < low;
@@ -207,6 +223,7 @@ export function classifyDeviation(
     outside: above || below,
     direction: above ? "above" : below ? "below" : "in",
     daysAgo,
+    ...(basis ? { basis } : {}),
   };
 }
 
@@ -241,7 +258,7 @@ async function readLatestDayMean(
   windowDays: number,
   now: Date,
   tz: string,
-): Promise<{ value: number; day: string } | null> {
+): Promise<{ value: number; day: string; lastAt: Date } | null> {
   const since = new Date(now.getTime() - windowDays * MS_PER_DAY);
   const rows = await prisma.measurement.findMany({
     where: { userId, type, deletedAt: null, measuredAt: { gte: since } },
@@ -268,7 +285,7 @@ export function latestDayMeanFromRows(
   rows: readonly { value: number; measuredAt: Date }[],
   type: MeasurementType,
   tz: string,
-): { value: number; day: string } | null {
+): { value: number; day: string; lastAt: Date } | null {
   const usable = rows.filter((r) => isPlausibleMetricValue(type, r.value));
   if (usable.length === 0) return null;
   // Derive the most-recent day defensively (do not assume the DB ordering)
@@ -282,6 +299,7 @@ export function latestDayMeanFromRows(
   return {
     value: sameDay.reduce((s, r) => s + r.value, 0) / sameDay.length,
     day,
+    lastAt: new Date(Math.max(...sameDay.map((r) => r.measuredAt.getTime()))),
   };
 }
 
@@ -329,7 +347,14 @@ export async function computeCoincidentDeviation(
       const sameHours =
         latest && latest.day === todayKey && SAME_HOURS_TYPES.has(type)
           ? sameHoursStanding(
-              await readSameHoursDays(userId, type, windowDays, now, tz),
+              await readSameHoursDays(
+                userId,
+                type,
+                windowDays,
+                now,
+                tz,
+                latest.lastAt,
+              ),
               todayKey,
               type,
             )
@@ -357,6 +382,7 @@ export async function computeCoincidentDeviation(
             sameHours.high,
             sameHours.center,
             0,
+            "sameHours",
           )
         : classifyDeviation(
             type,
diff --git a/src/lib/insights/health-status.ts b/src/lib/insights/health-status.ts
index a1dc31092..358059b6e 100644
--- a/src/lib/insights/health-status.ts
+++ b/src/lib/insights/health-status.ts
@@ -30,6 +30,12 @@ export interface HealthStatusDeviation {
   high: number;
   /** Which side of the band the value falls on. */
   direction: "above" | "below";
+  /**
+   * What the band describes: the whole day (`day`), or the same hours of the
+   * earlier days (`sameHours`), for a day still in progress whose mean moves
+   * with the hour (glucose). A surface naming the range says which.
+   */
+  basis: "day" | "sameHours";
 }
 
 /** One dated, sustained level shift from the changepoint detector. */
@@ -75,6 +81,7 @@ export function summariseHealthStatus(
       low: v.low,
       high: v.high,
       direction: v.direction === "above" ? "above" : "below",
+      basis: v.basis ?? "day",
     }));
 
   const mappedShifts: HealthStatusShift[] = shifts.map((s) => ({
diff --git a/src/lib/openapi/routes/insights-signals.ts b/src/lib/openapi/routes/insights-signals.ts
index 988f2f68f..b08885b3d 100644
--- a/src/lib/openapi/routes/insights-signals.ts
+++ b/src/lib/openapi/routes/insights-signals.ts
@@ -28,6 +28,11 @@ const healthStatusResponse = z
         low: z.number(),
         high: z.number(),
         direction: z.enum(["above", "below"]),
+        basis: z
+          .enum(["day", "sameHours"])
+          .describe(
+            "What `low`/`high` describe: the usual whole day (`day`), or the usual range for this time of day (`sameHours`), used for a day still in progress whose mean moves with the hour (glucose). Additive since v1.40.3.",
+          ),
       }),
     ),
     shifts: z.array(