diff --git a/frontend/static/app.js b/frontend/static/app.js
index 4b21646..c8a97b8 100644
--- a/frontend/static/app.js
+++ b/frontend/static/app.js
@@ -152,10 +152,27 @@ async function runGrade() {
   updateHash();
   placeholder.hidden = true;
   results.hidden = false;
-  // Omit the date when it's today, so the URL (and cache key) matches the prefetch
-  // fired from the other views — a same-tab navigation then reuses the response.
-  const q = `lat=${selected.lat}&lon=${selected.lon}`;
-  const url = dateInput.value === todayISO() ? uv(`grade?${q}`) : uv(`grade?${q}&date=${dateInput.value}`);
+  // Always send the target date, even when it's "today" — the backend only
+  // falls back to its own UTC today (api_grade's `date` param default; see
+  // backend/web/app.py) when the param is omitted or empty, a day behind local
+  // midnight for any viewer east of UTC (reported from Kaunas, UTC+3: asking
+  // for 7/26 rendered 7/25). The comment this replaces claimed omitting the
+  // date kept this URL matching the cross-view prefetch — but that match was
+  // the other half of the bug: cache.js's viewFetches() seeds the grade view's
+  // cache entry under this exact dateless URL too, tagged fresh for the
+  // viewer's local day no matter which day the server actually resolved, so a
+  // same-tab nav that had already prefetched this cell (e.g. via the Day page)
+  // could serve that stale, server-resolved slice straight out of IndexedDB
+  // with no live request ever going out. Sending the real date makes every
+  // load self-consistent with the viewer's own clock instead of aliasing onto
+  // whatever "today" the server or an earlier prefetch resolved.
+  // dateInput.value can also come back empty (a cleared native date field —
+  // day.js guards the same input for the same reason), so fall back to the
+  // viewer's local today rather than ever send `date=` empty, which hits that
+  // same server fallback.
+  const date = dateInput.value || todayISO();
+  const q = `lat=${selected.lat}&lon=${selected.lon}&date=${date}`;
+  const url = uv(`grade?${q}`);
   await loadView({
     url, ttl: TTL.grade, seq: ++gradeSeq, current: () => gradeSeq,
     spinner: () => { results.innerHTML = `<p class="spinner">Fetching decades of climate history…</p>`; },