diff --git a/src/DashboardService.php b/src/DashboardService.php
index 0032b69..6df5f62 100644
--- a/src/DashboardService.php
+++ b/src/DashboardService.php
@@ -123,11 +123,18 @@ final class DashboardService
             return ['days' => [], 'stale' => true];
         }
         $result = $this->fetch('forecast', fn() => $this->source->forecast($lat, $lon, $tz->getName()), self::ERR_FORECAST);
-        if ($result['data'] === null) {
-            return ['days' => [], 'stale' => $result['stale']];
+        $daily = is_array($result['data']['daily'] ?? null) ? $result['data']['daily'] : null;
+        if ($daily === null) {
+            // Data ontbreekt (echte storing, al gemeld door fetch()), of de cache staat nog in een ouder
+            // formaat na een deploy dat de opgeslagen vorm wijzigde. In beide gevallen liever zichtbaar
+            // niets tonen dan stil een lege verwachting zonder foutmelding.
+            if ($result['data'] !== null) {
+                $this->addError(self::ERR_FORECAST);
+            }
+            return ['days' => [], 'stale' => true];
         }
 
-        $days = ForecastMapper::map($result['data']['daily'] ?? []);
+        $days = ForecastMapper::map($daily);
         $hourlyByDate = HourlyForecastMapper::mapByDate($result['data']['hourly'] ?? [], $tz);
         foreach ($days as &$day) {
             $day['hourly'] = $hourlyByDate[$day['date']] ?? [];
diff --git a/tests/DashboardServiceTest.php b/tests/DashboardServiceTest.php
index 0b05402..a562ab3 100644
--- a/tests/DashboardServiceTest.php
+++ b/tests/DashboardServiceTest.php
@@ -182,6 +182,22 @@ final class DashboardServiceTest extends TestCase
         self::assertSame(16.4, $p['outdoor']['temp']);
     }
 
+    public function testLegacyCachedForecastShapeIsTreatedAsUnavailableNotSilentlyEmpty(): void
+    {
+        // Vóór 2026-09-13 cachete DashboardService het platte "daily"-blok direct onder de sleutel
+        // "forecast". Na de uitbreiding met uurdata verwacht de code {daily, hourly}. Een nog niet
+        // verlopen cache in het oude formaat mag niet stil een lege verwachting zonder foutmelding geven.
+        $legacyDailyOnly = json_decode((string) file_get_contents(__DIR__ . '/fixtures/forecast.json'), true)['daily'];
+        (new Cache($this->dir))->write('forecast', $legacyDailyOnly, (new \DateTimeImmutable('2026-09-11 12:30:00 UTC'))->getTimestamp());
+
+        $p = $this->service()->build();
+
+        self::assertSame([], $p['forecast']);
+        self::assertTrue($p['forecast_stale']);
+        self::assertSame(['forecast_unavailable'], $p['errors']);
+        self::assertSame(0, $this->source->calls['forecast'], 'de cache was nog vers, dus geen live call verwacht');
+    }
+
     public function testSecondBuildWithinTtlUsesCache(): void
     {
         $this->service()->build();