diff --git a/avian/frontend/apt.js b/avian/frontend/apt.js
index 6923c87..05504b0 100644
--- a/avian/frontend/apt.js
+++ b/avian/frontend/apt.js
@@ -160,15 +160,29 @@
   applySiteTitle(siteTitle);
 
   var winBtns = [].slice.call(winPick.querySelectorAll('button'));
-  var currentHours = +readLS('bird:window', '24') || 24;
+  var START_HOUR = +(readLS('bird:todayStart', '6')) || 6;
+  var windowMode = readLS('bird:window', '24');
+  var currentHours = windowMode === 'today' ? todayHours() : (+windowMode || 24);
+  function todayHours() {
+    var now = new Date();
+    var start = new Date(now); start.setHours(START_HOUR, 0, 0, 0);
+    if (now < start) start.setDate(start.getDate() - 1);
+    return Math.max(1, (now - start) / 3600000);
+  }
+  function effectiveHours() {
+    if (windowMode === 'today') { currentHours = todayHours(); }
+    return currentHours;
+  }
   winBtns.forEach(function (b) {
-    b.setAttribute('aria-current', (+b.dataset.h === currentHours) ? 'true' : 'false');
+    var match = windowMode === 'today' ? b.dataset.h === 'today' : +b.dataset.h === currentHours;
+    b.setAttribute('aria-current', match ? 'true' : 'false');
   });
   winBtns.forEach(function (b) {
     b.addEventListener('click', function () {
       winBtns.forEach(function (x) { x.setAttribute('aria-current', x === b ? 'true' : 'false'); });
-      currentHours = +b.dataset.h;
-      writeLS('bird:window', String(currentHours));
+      windowMode = b.dataset.h;
+      currentHours = windowMode === 'today' ? todayHours() : +windowMode;
+      writeLS('bird:window', windowMode);
       syncPill(winPick);
       // Actual data refresh is wired below via refreshRecent().
     });
@@ -850,9 +864,10 @@
   // a bare "window" with the span it actually covers. Thresholds match
   // the winPick buttons (1H / 12H / 24H / 7D / ALL).
   function windowLabel(h) {
+    if (windowMode === 'today') return 'today';
     if (h <= 1) return 'this hour';
     if (h <= 12) return 'past 12h';
-    if (h <= 24) return 'today';
+    if (h <= 24) return 'past 24h';
     if (h <= 168) return 'this week';
     return 'all time';
   }
@@ -1381,8 +1396,8 @@
     // changes the picker again before it resolves - or a slower poll
     // lands later - we discard the stale response so the collage
     // never reverts to a different window.
-    var forHours = currentHours;
-    return fetchJson('./avian/api/birdnet-api.php?action=recent&hours=' + forHours)
+    var forHours = effectiveHours();
+    return fetchJson('./avian/api/birdnet-api.php?action=recent&hours=' + Math.round(forHours))
       .then(function (j) {
         if (forHours !== currentHours) return; // window changed mid-flight
         DATA.recent = j; renderWindowDependent(animate);
@@ -1390,13 +1405,13 @@
       .catch(function (e) { console.warn('recent fetch failed', e); });
   }
   function refreshAll(animate) {
-    var forHours = currentHours;
+    var forHours = effectiveHours();
     return Promise.all([
       fetchJson('./avian/api/birdnet-api.php?action=stats').catch(function () { return null; }),
       fetchJson('./avian/api/birdnet-api.php?action=lifelist').catch(function () { return null; }),
       fetchJson('./avian/api/birdnet-api.php?action=timeseries&days=30').catch(function () { return null; }),
       fetchJson('./avian/api/birdnet-api.php?action=firstseen&limit=10').catch(function () { return null; }),
-      fetchJson('./avian/api/birdnet-api.php?action=recent&hours=' + forHours).catch(function () { return null; }),
+      fetchJson('./avian/api/birdnet-api.php?action=recent&hours=' + Math.round(forHours)).catch(function () { return null; }),
     ]).then(function (parts) {
       DATA.stats = parts[0];
       DATA.lifelist = parts[1];
@@ -1817,8 +1832,39 @@
       + '  <input type="text" class="title-input" data-title-input maxlength="40" value="' + adminEsc(siteTitle) + '" placeholder="your birds">'
       + '</div>';
   }
+  function todayStartRow() {
+    var h = START_HOUR;
+    var label = (h === 0 ? '12' : h > 12 ? '' + (h - 12) : '' + h) + ':00 ' + (h < 12 ? 'AM' : 'PM');
+    return ''
+      + '<div class="slider-row">'
+      + '  <div class="head">'
+      + '    <div class="label-block">'
+      + '      <span class="label">Today starts at</span>'
+      + '      <span class="hint">when the TODAY window resets</span>'
+      + '    </div>'
+      + '    <span class="value" data-value-for="todayStart">' + label + '</span>'
+      + '  </div>'
+      + '  <div class="slider-track">'
+      + '    <input type="range" min="0" max="12" step="1" value="' + h + '" data-today-start>'
+      + '  </div>'
+      + '</div>';
+  }
   function wireSettingsControls(scope) {
     scope = scope || document;
+    var todaySlider = scope.querySelector('[data-today-start]');
+    if (todaySlider) {
+      todaySlider.addEventListener('input', function () {
+        var h = +todaySlider.value;
+        var label = (h === 0 ? '12' : h > 12 ? '' + (h - 12) : '' + h) + ':00 ' + (h < 12 ? 'AM' : 'PM');
+        var valEl = scope.querySelector('[data-value-for="todayStart"]');
+        if (valEl) valEl.textContent = label;
+      });
+      todaySlider.addEventListener('change', function () {
+        START_HOUR = +todaySlider.value;
+        writeLS('bird:todayStart', String(START_HOUR));
+        if (windowMode === 'today') { currentHours = todayHours(); refreshRecent(true); }
+      });
+    }
     scope.querySelectorAll('.switch').forEach(function (sw) {
       sw.addEventListener('click', function () {
         var on = sw.getAttribute('aria-checked') !== 'true';
@@ -2389,6 +2435,7 @@
           '<div class="admin-settings">'
           + themeRow()
           + titleRow()
+          + todayStartRow()
           + settingsToggle('preserve', 'Preserve all recordings', "don't auto-delete", preserve)
           + settingsSlider('CONFIDENCE',  'Confidence threshold', 'min score to log a detection', v.CONFIDENCE,  0.1, 0.95, 0.05, 2)
           + settingsSlider('SENSITIVITY', 'Sensitivity',          'analyzer sensitivity',          v.SENSITIVITY, 0.5, 1.5,  0.05, 2)
diff --git a/avian/frontend/index.html b/avian/frontend/index.html
index e175704..432b134 100644
--- a/avian/frontend/index.html
+++ b/avian/frontend/index.html
@@ -27,6 +27,7 @@
   <div class="window-pick" id="winPick" role="tablist">
     <i class="seg-pill" aria-hidden="true"></i>
     <button data-h="1"   type="button">1H</button>
+    <button data-h="today" type="button">TODAY</button>
     <button data-h="12"  type="button">12H</button>
     <button data-h="24"  type="button" aria-current="true">24H</button>
     <button data-h="168" type="button">7D</button>