diff --git a/clio-ui/components/App.jsx b/clio-ui/components/App.jsx
index 0af2466..bef834f 100644
--- a/clio-ui/components/App.jsx
+++ b/clio-ui/components/App.jsx
@@ -18,6 +18,14 @@ function clearStoredApiKey() {
   localStorage.removeItem(API_KEY_STORAGE_KEY);
 }
 
+// Get local date string in YYYY-MM-DD format (not UTC)
+function toLocalDateString(date) {
+  const year = date.getFullYear();
+  const month = String(date.getMonth() + 1).padStart(2, '0');
+  const day = String(date.getDate()).padStart(2, '0');
+  return `${year}-${month}-${day}`;
+}
+
 // Authenticated fetch wrapper
 async function authFetch(url, options = {}) {
   const apiKey = getStoredApiKey();
@@ -364,7 +372,7 @@ function App() {
           setSelectedDayState(route.day);
         } else if (recordings.length > 0) {
           const sorted = [...recordings].sort((a, b) => b.startTime - a.startTime);
-          setSelectedDayState(sorted[0].startTime.toISOString().slice(0, 10));
+          setSelectedDayState(toLocalDateString(sorted[0].startTime));
         }
 
         // If URL has a recording ID, fetch it
@@ -503,7 +511,7 @@ function App() {
 }
 
 // Export utilities for other components
-Object.assign(window, { authFetch, getStoredApiKey });
+Object.assign(window, { authFetch, getStoredApiKey, toLocalDateString });
 
 const root = ReactDOM.createRoot(document.getElementById('root'));
 root.render(<App />);
diff --git a/clio-ui/components/Dashboard.jsx b/clio-ui/components/Dashboard.jsx
index 4fb3ea5..cbff06a 100644
--- a/clio-ui/components/Dashboard.jsx
+++ b/clio-ui/components/Dashboard.jsx
@@ -22,7 +22,7 @@ function Dashboard({ data, setView, setSelectedDay, setSelectedRecording }) {
   // Build day map
   const dayMap = {};
   for (const r of data.recordings) {
-    const key = r.startTime.toISOString().slice(0, 10);
+    const key = window.toLocalDateString(r.startTime);
     if (!dayMap[key]) dayMap[key] = { count: 0, minutes: 0 };
     dayMap[key].count++;
     dayMap[key].minutes += r.durationMinutes;
@@ -145,7 +145,7 @@ function CalendarHeatmap({ dayMap, maxMinutes, onDayClick }) {
         for (let d = 1; d <= daysInMonth; d++) {
           const dateStr = `${year}-${String(month + 1).padStart(2, '0')}-${String(d).padStart(2, '0')}`;
           const info = dayMap[dateStr];
-          const isToday = dateStr === new Date().toISOString().slice(0, 10);
+          const isToday = dateStr === window.toLocalDateString(new Date());
           cells.push(
             <div
               key={d}
diff --git a/clio-ui/components/DayView.jsx b/clio-ui/components/DayView.jsx
index 53dff61..ed2e2ec 100644
--- a/clio-ui/components/DayView.jsx
+++ b/clio-ui/components/DayView.jsx
@@ -14,7 +14,7 @@ function DayView({ data, selectedDay, setSelectedDay, setSelectedRecording, setV
   // Build day map
   const dayMap = {};
   for (const r of data.recordings) {
-    const key = r.startTime.toISOString().slice(0, 10);
+    const key = window.toLocalDateString(r.startTime);
     if (!dayMap[key]) dayMap[key] = [];
     dayMap[key].push(r);
   }
@@ -79,7 +79,7 @@ function DayView({ data, selectedDay, setSelectedDay, setSelectedRecording, setV
             const dateStr = `${year}-${String(month + 1).padStart(2, '0')}-${String(d).padStart(2, '0')}`;
             const recs = dayMap[dateStr] || [];
             const isSelected = selectedDay === dateStr;
-            const isToday = dateStr === now.toISOString().slice(0, 10);
+            const isToday = dateStr === window.toLocalDateString(now);
             const hasRecs = recs.length > 0;
             const intensity = hasRecs ? recs.length / maxCount : 0;