diff --git a/custom_components/irm_kmi/coordinator.py b/custom_components/irm_kmi/coordinator.py
index b433c3a..39e576f 100644
--- a/custom_components/irm_kmi/coordinator.py
+++ b/custom_components/irm_kmi/coordinator.py
@@ -440,8 +440,8 @@ class IrmKmiCoordinator(TimestampDataUpdateCoordinator):
                 wind_bearing=wind_bearing,
                 is_daytime=is_daytime,
                 text=f.get('text', {}).get(lang, ""),
-                sunrise=sunrise,
-                sunset=sunset
+                sunrise=sunrise.isoformat() if sunrise is not None else None,
+                sunset=sunset.isoformat() if sunset is not None else None
             )
             # Swap temperature and templow if needed
             if (forecast['native_templow'] is not None
diff --git a/custom_components/irm_kmi/data.py b/custom_components/irm_kmi/data.py
index 566155f..ea7d32d 100644
--- a/custom_components/irm_kmi/data.py
+++ b/custom_components/irm_kmi/data.py
@@ -10,8 +10,8 @@ class IrmKmiForecast(Forecast):
 
     # TODO: add condition_2 as well and evolution to match data from the API?
     text: str | None
-    sunrise: datetime | None
-    sunset: datetime | None
+    sunrise: str | None
+    sunset: str | None
 
 
 class IrmKmiRadarForecast(Forecast):
diff --git a/custom_components/irm_kmi/sensor.py b/custom_components/irm_kmi/sensor.py
index 577ea2a..64aaf0f 100644
--- a/custom_components/irm_kmi/sensor.py
+++ b/custom_components/irm_kmi/sensor.py
@@ -1,5 +1,5 @@
 """Sensor for pollen from the IRM KMI"""
-import datetime
+from datetime import datetime
 import logging
 
 from homeassistant.components import sensor
@@ -74,7 +74,7 @@ class IrmKmiNextWarning(CoordinatorEntity, SensorEntity):
         self._attr_translation_key = f"next_warning"
 
     @property
-    def native_value(self) -> datetime.datetime | None:
+    def native_value(self) -> datetime | None:
         """Return the timestamp for the start of the next warning.  Is None when no future warning are available"""
         if self.coordinator.data.get('warnings') is None:
             return None
@@ -124,12 +124,13 @@ class IrmKmiNextSunMove(CoordinatorEntity, SensorEntity):
         self._attr_icon = 'mdi:weather-sunset-down' if move == 'sunset' else 'mdi:weather-sunset-up'
 
     @property
-    def native_value(self) -> datetime.datetime | None:
+    def native_value(self) -> datetime | None:
         """Return the timestamp for the next sunrise or sunset"""
         now = dt.now()
         data: list[IrmKmiForecast] = self.coordinator.data.get('daily_forecast')
 
-        upcoming = [f.get(self._move) for f in data if f.get(self._move) >= now]
+        upcoming = [datetime.fromisoformat(f.get(self._move)) for f in data
+                    if f.get(self._move) is not None and datetime.fromisoformat(f.get(self._move)) >= now]
 
         if len(upcoming) > 0:
             return upcoming[0]
diff --git a/tests/test_coordinator.py b/tests/test_coordinator.py
index dd6704b..95fa4d9 100644
--- a/tests/test_coordinator.py
+++ b/tests/test_coordinator.py
@@ -102,7 +102,6 @@ async def test_daily_forecast(
     assert len(result) == 8
     assert result[0]['datetime'] == '2023-12-26'
     assert not result[0]['is_daytime']
-    tz = zoneinfo.ZoneInfo(key='Europe/Brussels')
     expected = IrmKmiForecast(
         datetime='2023-12-27',
         condition=ATTR_CONDITION_PARTLYCLOUDY,
@@ -115,8 +114,8 @@ async def test_daily_forecast(
         wind_bearing=180,
         is_daytime=True,
         text='Bar',
-        sunrise=datetime.fromisoformat("2023-12-27T08:44:00+01:00").astimezone(tz),
-        sunset=datetime.fromisoformat("2023-12-27T16:43:00+01:00").astimezone(tz)
+        sunrise="2023-12-27T08:44:00+01:00",
+        sunset="2023-12-27T16:43:00+01:00"
     )
 
     assert result[1] == expected
@@ -365,14 +364,14 @@ async def test_sunrise_sunset_nl(
     coordinator = IrmKmiCoordinator(hass, mock_config_entry)
     result = await coordinator.daily_list_to_forecast(api_data)
 
-    assert result[0]['sunrise'].isoformat() == '2024-06-09T05:19:28+02:00'
-    assert result[0]['sunset'].isoformat() == '2024-06-09T22:01:09+02:00'
+    assert result[0]['sunrise'] == '2024-06-09T05:19:28+02:00'
+    assert result[0]['sunset'] == '2024-06-09T22:01:09+02:00'
 
     assert result[1]['sunrise'] is None
     assert result[1]['sunset'] is None
 
-    assert result[2]['sunrise'].isoformat() == '2024-06-10T05:19:08+02:00'
-    assert result[2]['sunset'].isoformat() == '2024-06-10T22:01:53+02:00'
+    assert result[2]['sunrise'] == '2024-06-10T05:19:08+02:00'
+    assert result[2]['sunset'] == '2024-06-10T22:01:53+02:00'
 
 
 @freeze_time("2023-12-26T18:30:00+01:00")
@@ -385,8 +384,8 @@ async def test_sunrise_sunset_be(
     coordinator = IrmKmiCoordinator(hass, mock_config_entry)
     result = await coordinator.daily_list_to_forecast(api_data)
 
-    assert result[1]['sunrise'].isoformat() == '2023-12-27T08:44:00+01:00'
-    assert result[1]['sunset'].isoformat() == '2023-12-27T16:43:00+01:00'
+    assert result[1]['sunrise'] == '2023-12-27T08:44:00+01:00'
+    assert result[1]['sunset'] == '2023-12-27T16:43:00+01:00'
 
-    assert result[2]['sunrise'].isoformat() == '2023-12-28T08:45:00+01:00'
-    assert result[2]['sunset'].isoformat() == '2023-12-28T16:43:00+01:00'
+    assert result[2]['sunrise'] == '2023-12-28T08:45:00+01:00'
+    assert result[2]['sunset'] == '2023-12-28T16:43:00+01:00'