diff --git a/public/index.php b/public/index.php
index 7bd0dd9..858fdfb 100644
--- a/public/index.php
+++ b/public/index.php
@@ -31,6 +31,94 @@ if (!function_exists('formatDurationHoursMinutes')) {
         return sprintf('%d Minuten', $restMinutes);
     }
 }
+if (!function_exists('eventDateTime')) {
+    function eventDateTime(array $event): ?DateTimeImmutable
+    {
+        if (empty($event['found']) || empty($event['local_iso'])) {
+            return null;
+        }
+
+        try {
+            return new DateTimeImmutable((string)$event['local_iso']);
+        } catch (Exception) {
+            return null;
+        }
+    }
+}
+if (!function_exists('intervalOverlapSeconds')) {
+    function intervalOverlapSeconds(?DateTimeImmutable $aStart, ?DateTimeImmutable $aEnd, ?DateTimeImmutable $bStart, ?DateTimeImmutable $bEnd): int
+    {
+        if ($aStart === null || $aEnd === null || $bStart === null || $bEnd === null) {
+            return 0;
+        }
+
+        $start = max($aStart->getTimestamp(), $bStart->getTimestamp());
+        $end = min($aEnd->getTimestamp(), $bEnd->getTimestamp());
+
+        return max(0, $end - $start);
+    }
+}
+if (!function_exists('planetVisibleIntervalsForDay')) {
+    function planetVisibleIntervalsForDay(array $planet, DateTimeImmutable $dayStart, DateTimeImmutable $dayEnd): array
+    {
+        $rise = eventDateTime($planet['rise'] ?? []);
+        $set = eventDateTime($planet['set'] ?? []);
+
+        if ($rise && $set) {
+            if ($rise <= $set) {
+                return [[$rise, $set]];
+            }
+
+            return [
+                [$dayStart, $set],
+                [$rise, $dayEnd],
+            ];
+        }
+
+        if ($rise) {
+            return [[$rise, $dayEnd]];
+        }
+
+        if ($set) {
+            return [[$dayStart, $set]];
+        }
+
+        return [];
+    }
+}
+if (!function_exists('planetVisibilityClass')) {
+    function planetVisibilityClass(array $planet, DateTimeImmutable $dayStart, DateTimeImmutable $dayEnd, array $ev, array $evNext): array
+    {
+        $intervals = planetVisibleIntervalsForDay($planet, $dayStart, $dayEnd);
+        if ($intervals === []) {
+            return ['class' => 'planet-visibility-bad', 'label' => 'am Tag'];
+        }
+
+        $astroDusk = eventDateTime($ev['astro_dusk'] ?? []);
+        $astroDawnNext = eventDateTime($evNext['astro_dawn'] ?? []);
+        $civilDusk = eventDateTime($ev['civil_dusk'] ?? []);
+        $civilDawnNext = eventDateTime($evNext['civil_dawn'] ?? []);
+
+        $nightSeconds = 0;
+        $twilightSeconds = 0;
+
+        foreach ($intervals as [$from, $to]) {
+            $nightSeconds += intervalOverlapSeconds($from, $to, $astroDusk, $astroDawnNext);
+            $twilightSeconds += intervalOverlapSeconds($from, $to, $civilDusk, $astroDusk);
+            $twilightSeconds += intervalOverlapSeconds($from, $to, $astroDawnNext, $civilDawnNext);
+        }
+
+        if ($nightSeconds > 0) {
+            return ['class' => 'planet-visibility-good', 'label' => 'nachts gut'];
+        }
+
+        if ($twilightSeconds > 0) {
+            return ['class' => 'planet-visibility-warn', 'label' => 'in der Daemmerung'];
+        }
+
+        return ['class' => 'planet-visibility-bad', 'label' => 'am Tag'];
+    }
+}
 
 function idx_tleChecksum(string $line): int
 {
@@ -281,6 +369,35 @@ if ($loggedIn) {
 }
 ?>
 <?php require __DIR__ . '/header.php'; ?>
+<style>
+.planet-visibility-good {
+    color: #4fb36a;
+}
+
+.planet-visibility-good + .riseset-val,
+.planet-visibility-good + .riseset-val + .riseset-val {
+    color: #4fb36a;
+}
+
+.planet-visibility-warn {
+    color: #d9a441;
+}
+
+.planet-visibility-warn + .riseset-val,
+.planet-visibility-warn + .riseset-val + .riseset-val {
+    color: #d9a441;
+}
+
+.planet-visibility-bad {
+    color: #cf5a5a;
+}
+
+.planet-visibility-bad + .riseset-val,
+.planet-visibility-bad + .riseset-val + .riseset-val {
+    color: #cf5a5a;
+}
+
+</style>
 
 <?php if (!$loggedIn): ?>
 
@@ -310,6 +427,8 @@ if ($loggedIn) {
         <?php
         $ev = $skyData['events'] ?? [];
         $evNext = $skyDataNext['events'] ?? [];
+        $dayStartLocal = new DateTimeImmutable($date . ' 00:00:00', new DateTimeZone($tz));
+        $dayEndLocal = $dayStartLocal->modify('+1 day');
         $deepSkyStart = (!empty($ev['astro_dusk']['found']) && !empty($ev['astro_dusk']['local_iso']))
             ? new DateTimeImmutable($ev['astro_dusk']['local_iso'])
             : null;
@@ -348,7 +467,8 @@ if ($loggedIn) {
                 <span class="riseset-sep"></span><span class="riseset-sep"></span><span class="riseset-sep"></span>
 
                 <?php foreach (($planetData['planets'] ?? []) as $planet): ?>
-                <span class="riseset-label"><?= h($planet['name']) ?></span>
+                <?php $planetVisibility = planetVisibilityClass($planet, $dayStartLocal, $dayEndLocal, $ev, $evNext); ?>
+                <span class="riseset-label <?= h($planetVisibility['class']) ?>" title="<?= h($planetVisibility['label']) ?>"><?= h($planet['name']) ?></span>
                 <span class="riseset-val">↑ <?= ($planet['rise']['found'] ?? false) ? h($planet['rise']['local_time']) : '—' ?></span>
                 <span class="riseset-val">↓ <?= ($planet['set']['found']  ?? false) ? h($planet['set']['local_time'])  : '—' ?></span>
                 <?php endforeach; ?>