diff --git a/src/components/cycle/log-day-sheet.tsx b/src/components/cycle/log-day-sheet.tsx
index ebb633514..815b77df7 100644
--- a/src/components/cycle/log-day-sheet.tsx
+++ b/src/components/cycle/log-day-sheet.tsx
@@ -479,10 +479,19 @@ function CervixRow<T extends string>({
  * deliberately: it is how people recognise a date they are recalling.
  */
 export function formatSheetDate(date: string, locale: Locale): string {
-  const [year, month, day] = date.split("-").map(Number);
-  return new Date(year, month - 1, day).toLocaleDateString(
+  // A cycle day key is a calendar day, not an instant, so it is anchored at
+  // noon UTC and rendered in UTC — the same anchor the domain's day arithmetic
+  // uses. Formatting it in the browser's zone would let a reader east or west
+  // of it see the sheet name a different day than the one it writes to.
+  return new Date(`${date}T12:00:00Z`).toLocaleDateString(
     resolveIntlLocale(locale),
-    { weekday: "long", day: "numeric", month: "long", year: "numeric" },
+    {
+      weekday: "long",
+      day: "numeric",
+      month: "long",
+      year: "numeric",
+      timeZone: "UTC",
+    },
   );
 }
 
diff --git a/src/components/cycle/use-cycle.ts b/src/components/cycle/use-cycle.ts
index d21060e30..0e8b4fd22 100644
--- a/src/components/cycle/use-cycle.ts
+++ b/src/components/cycle/use-cycle.ts
@@ -20,6 +20,7 @@ import {
   apiPost,
 } from "@/lib/api/api-fetch";
 import { useTranslations } from "@/lib/i18n/context";
+import { toastWrittenOutcome } from "@/components/outcome/outcome-toast";
 
 import {
   cycleDependentKeys,
@@ -247,7 +248,7 @@ export function useLogDay() {
     },
     onSuccess: () => {
       void invalidateKeys(qc, cycleDependentKeys);
-      toast.success(t("cycle.saveSuccess"));
+      toastWrittenOutcome("success", t("cycle.saveSuccess"));
     },
   });
 }
@@ -293,7 +294,7 @@ export function usePatchDayLog() {
     },
     onSuccess: () => {
       void invalidateKeys(qc, cycleDependentKeys);
-      toast.success(t("cycle.saveSuccess"));
+      toastWrittenOutcome("success", t("cycle.saveSuccess"));
     },
   });
 }
@@ -311,7 +312,7 @@ export function useStartPeriod() {
     },
     onSuccess: () => {
       void invalidateKeys(qc, cycleDependentKeys);
-      toast.success(t("cycle.periodStartSaved"));
+      toastWrittenOutcome("success", t("cycle.periodStartSaved"));
     },
     // v1.16.4 — period boundaries had no failure signal at all (the sheet
     // simply stayed open); a toast names the rejection.
@@ -333,7 +334,7 @@ export function useEndPeriod() {
     },
     onSuccess: () => {
       void invalidateKeys(qc, cycleDependentKeys);
-      toast.success(t("cycle.periodEndSaved"));
+      toastWrittenOutcome("success", t("cycle.periodEndSaved"));
     },
     onError: () => toast.error(t("cycle.saveError")),
   });
@@ -349,7 +350,7 @@ export function useDeleteDayLog() {
     },
     onSuccess: () => {
       void invalidateKeys(qc, cycleDependentKeys);
-      toast.success(t("cycle.deleteSuccess"));
+      toastWrittenOutcome("success", t("cycle.deleteSuccess"));
     },
     onError: () => toast.error(t("cycle.deleteError")),
   });