diff --git a/src/lib/consistency-score.ts b/src/lib/consistency-score.ts
index 66b9604a5..d7ac2ab34 100644
--- a/src/lib/consistency-score.ts
+++ b/src/lib/consistency-score.ts
@@ -133,7 +133,7 @@ export function calculateConsistencyScore(
   activeDates: Set<string>,
   timeZone = "UTC",
 ): ConsistencyScoreResult {
-  const sortedDates = Array.from(activeDates).sort();
+  const sortedDates = Array.from(activeDates).sort((a, b) => a - b);
   const today = todayInTimezone(timeZone);
 
   const weeklyConsistency = computeWeeklyConsistency(activeDates);
diff --git a/src/lib/streak-utils.ts b/src/lib/streak-utils.ts
index ae8b24d7b..3bf616253 100644
--- a/src/lib/streak-utils.ts
+++ b/src/lib/streak-utils.ts
@@ -20,7 +20,7 @@ function getSortedUniqueDays(dates: StreakDate[]): string[] {
     if (key) dayKeys.add(key);
   }
 
-  return Array.from(dayKeys).sort();
+  return Array.from(dayKeys).sort((a, b) => a - b);
 }
 
 function getRuns(dates: StreakDate[]): { end: string; length: number }[] {