diff --git a/src/app/api/dashboard/chart-overlay-prefs/route.ts b/src/app/api/dashboard/chart-overlay-prefs/route.ts
index 1a84a9cd1..ac9d4cd07 100644
--- a/src/app/api/dashboard/chart-overlay-prefs/route.ts
+++ b/src/app/api/dashboard/chart-overlay-prefs/route.ts
@@ -44,6 +44,12 @@ const prefsSchema = z.object({
     comparisonBaseline: z
       .enum(["none", "lastMonth", "lastYear"])
       .default("none"),
+    // v1.30.1 — persisted range-tab selection (M2 QoL fix). Optional so
+    // a client on an older cached bundle that never sends it doesn't
+    // 422. Literal set mirrors `CHART_RANGE_POINTS` in dashboard-layout.
+    rangePoints: z
+      .union([z.literal(0), z.literal(7), z.literal(30), z.literal(90)])
+      .optional(),
   }),
 });
 
diff --git a/src/components/charts/health-chart.tsx b/src/components/charts/health-chart.tsx
index ee68e1142..774f30e5e 100644
--- a/src/components/charts/health-chart.tsx
+++ b/src/components/charts/health-chart.tsx
@@ -632,6 +632,32 @@ export function HealthChart({
     ? overlayPrefs.prefs.comparisonBaseline
     : compareBaseline;
 
+  // v1.30.1 M2 — hydrate the range tab from the persisted prefs once
+  // they arrive, mirroring the overlay toggles above. A plain
+  // `useState(30)` initializer can't see the persisted value because
+  // the dashboard-layout query resolves after mount; `rangePoints` also
+  // drives several derived memos below by identity, so it stays local
+  // state (unlike the toggles, which read `overlayPrefs.prefs` live)
+  // and is synced in exactly once. `windowOverride` charts (mini mode)
+  // are pinned and never adopt a persisted range. Adjusted during
+  // render (React's documented "adjust state during render" escape
+  // hatch, not an effect — the lint rule that bans ref reads during
+  // render is why this is a second piece of state rather than a ref)
+  // so the very first render that sees the resolved prefs already
+  // reflects them; `rangeHydrated` guards against re-running past the
+  // first hit, so a later cache refetch can't stomp a range the user
+  // already picked this session.
+  const [rangeHydrated, setRangeHydrated] = useState(false);
+  if (
+    !windowOverride &&
+    chartKey &&
+    !rangeHydrated &&
+    typeof overlayPrefs.prefs.rangePoints === "number"
+  ) {
+    setRangeHydrated(true);
+    setRangePoints(overlayPrefs.prefs.rangePoints);
+  }
+
   // v1.4.19 A2 — viewport-aware tick density. Recharts' default is one
   // tick per data point; the helper caps that at 4-10 visible labels
   // depending on viewport width so the X-axis reads consistently across
@@ -1674,7 +1700,17 @@ export function HealthChart({
                   // v1.12.8 — a range-tab change re-slices `chartData`; the
                   // visible-range stats memo recomputes off the new slice and
                   // the stat strip follows automatically.
+                  setRangeHydrated(true);
                   setRangePoints(r.points);
+                  // v1.30.1 M2 — persist the pick per chart, same model
+                  // as the overlay toggles, so the range survives a
+                  // remount instead of resetting to 30 d every visit.
+                  if (chartKey && !windowOverride) {
+                    overlayPrefs.setPrefs({
+                      ...overlayPrefs.prefs,
+                      rangePoints: r.points,
+                    });
+                  }
                 }}
                 title={t(r.titleKey)}
                 data-slot="chart-range-tab"
diff --git a/src/components/charts/mood-chart.tsx b/src/components/charts/mood-chart.tsx
index 33715a22e..b1a81e5c8 100644
--- a/src/components/charts/mood-chart.tsx
+++ b/src/components/charts/mood-chart.tsx
@@ -323,6 +323,25 @@ export function MoodChart({
   const effectiveCompareBaseline =
     !mini && chartKey ? overlayPrefs.prefs.comparisonBaseline : compareBaseline;
 
+  // v1.30.1 M2 — hydrate the range tab from the persisted prefs once
+  // they arrive; see health-chart.tsx for the full rationale (the
+  // dashboard-layout query resolves after mount, and `rangePoints`
+  // stays local state because several memos depend on it by identity).
+  // Adjusted during render, not an effect — React's documented "adjust
+  // state during render" pattern (a second state flag rather than a
+  // ref, since the lint rule bans ref reads during render).
+  const [rangeHydrated, setRangeHydrated] = useState(false);
+  if (
+    !mini &&
+    !windowOverride &&
+    chartKey &&
+    !rangeHydrated &&
+    typeof overlayPrefs.prefs.rangePoints === "number"
+  ) {
+    setRangeHydrated(true);
+    setRangePoints(overlayPrefs.prefs.rangePoints);
+  }
+
   // v1.4.19 A2 — viewport-aware tick density helper.
   const viewportWidth = useViewportWidth();
 
@@ -1047,7 +1066,18 @@ export function MoodChart({
                 aria-pressed={rangePoints === r.points}
                 size="sm"
                 className="min-h-11 px-2 text-xs sm:px-3"
-                onClick={() => setRangePoints(r.points)}
+                onClick={() => {
+                  setRangeHydrated(true);
+                  setRangePoints(r.points);
+                  // v1.30.1 M2 — persist the pick per chart, same
+                  // model as the overlay toggles.
+                  if (chartKey && !windowOverride) {
+                    overlayPrefs.setPrefs({
+                      ...overlayPrefs.prefs,
+                      rangePoints: r.points,
+                    });
+                  }
+                }}
                 title={t(r.titleKey)}
                 data-slot="chart-range-tab"
               >
diff --git a/src/lib/dashboard-layout.ts b/src/lib/dashboard-layout.ts
index 8c42009ba..dcf249db0 100644
--- a/src/lib/dashboard-layout.ts
+++ b/src/lib/dashboard-layout.ts
@@ -306,11 +306,24 @@ export const CHART_OVERLAY_KEYS = [
 ] as const;
 export type ChartOverlayKey = (typeof CHART_OVERLAY_KEYS)[number];
 
+/**
+ * v1.30.1 — the range tabs (`7 / 30 / 90 / All`) every chart card
+ * exposes. `0` means "All". Shared here so both the client hook and
+ * the server route validate against the same closed set instead of
+ * each chart component re-declaring it.
+ */
+export const CHART_RANGE_POINTS = [0, 7, 30, 90] as const;
+export type ChartRangePoints = (typeof CHART_RANGE_POINTS)[number];
+
 export interface ChartOverlayPrefs {
   showTrendIndicator: boolean;
   showTrendArrow: boolean;
   showTargetRange: boolean;
   comparisonBaseline: ComparisonBaseline;
+  // v1.30.1 — persisted range-tab selection. Undefined = never saved
+  // for this chart yet, so the chart falls back to its own 30 d
+  // default rather than forcing every unopened chart to look "saved".
+  rangePoints?: ChartRangePoints;
 }
 
 export const DEFAULT_CHART_OVERLAY_PREFS: ChartOverlayPrefs = {
@@ -320,6 +333,13 @@ export const DEFAULT_CHART_OVERLAY_PREFS: ChartOverlayPrefs = {
   comparisonBaseline: "none",
 };
 
+function isChartRangePoints(value: unknown): value is ChartRangePoints {
+  return (
+    typeof value === "number" &&
+    (CHART_RANGE_POINTS as readonly number[]).includes(value)
+  );
+}
+
 export type ChartOverlayPrefsMap = Partial<
   Record<ChartOverlayKey, ChartOverlayPrefs>
 >;
@@ -338,6 +358,9 @@ function coerceChartOverlayPrefs(value: unknown): ChartOverlayPrefs {
     comparisonBaseline: isComparisonBaseline(candidate.comparisonBaseline)
       ? candidate.comparisonBaseline
       : "none",
+    rangePoints: isChartRangePoints(candidate.rangePoints)
+      ? candidate.rangePoints
+      : undefined,
   };
 }