diff --git a/custom_components/adaptive_lighting/switch.py b/custom_components/adaptive_lighting/switch.py
index 8eb86f8c..cfe073c1 100755
--- a/custom_components/adaptive_lighting/switch.py
+++ b/custom_components/adaptive_lighting/switch.py
@@ -1042,7 +1042,10 @@ class SunLightSettings:
         def _replace_time(date: datetime.datetime, key: str) -> datetime.datetime:
             time = getattr(self, f"{key}_time")
             date_time = datetime.datetime.combine(date, time)
-            utc_time = self.time_zone.localize(date_time).astimezone(dt_util.UTC)
+            try:  # HA ≤2021.05, https://github.com/basnijholt/adaptive-lighting/issues/128
+                utc_time = self.time_zone.localize(date_time).astimezone(dt_util.UTC)
+            except AttributeError: # HA ≥2021.06
+                utc_time = date_time.replace(tzinfo=dt_util.DEFAULT_TIME_ZONE).astimezone(dt_util.UTC)
             return utc_time
 
         location = self.astral_location