diff --git a/lib/forecast-utils.ts b/lib/forecast-utils.ts
index a3600a9..56fd340 100644
--- a/lib/forecast-utils.ts
+++ b/lib/forecast-utils.ts
@@ -91,5 +91,9 @@ export function getHourlyForecastForDay(hours: HourlyForecast[], date: string) {
 }
 
 export function isForecastHourPast(time: string) {
-  return time < getWarsawForecastHour();
+  const currentHour = getWarsawForecastHour();
+  const hourTimestamp = parseForecastHour(time);
+  const currentTimestamp = parseForecastHour(currentHour);
+  if (hourTimestamp === null || currentTimestamp === null) return time < currentHour;
+  return hourTimestamp < currentTimestamp;
 }