diff --git a/irm_kmi_api/data.py b/irm_kmi_api/data.py
index 97f6c95..969f2a3 100644
--- a/irm_kmi_api/data.py
+++ b/irm_kmi_api/data.py
@@ -1,6 +1,6 @@
 """Data classes for IRM KMI integration"""
 from datetime import datetime
-from enum import Enum
+from enum import StrEnum
 from typing import List, Required, TypedDict
 
 
@@ -36,7 +36,7 @@ class Forecast(TypedDict, total=False):
     is_daytime: bool | None  # Mandatory to use with forecast_twice_daily
 
 
-class ConditionEvol(Enum):
+class ConditionEvol(StrEnum):
     """Possible state for evolution between weather conditions"""
 
     ONE_WAY = 'one_way'
@@ -44,7 +44,7 @@ class ConditionEvol(Enum):
     STABLE = 'stable'
 
 
-class RadarStyle(Enum):
+class RadarStyle(StrEnum):
     """Possible style for the rain radar"""
 
     OPTION_STYLE_STD = 'standard_style'
@@ -53,7 +53,7 @@ class RadarStyle(Enum):
     OPTION_STYLE_SATELLITE = 'satellite_style'
 
 
-class PollenName(Enum):
+class PollenName(StrEnum):
     ALDER = 'alder'
     ASH = 'ash'
     BIRCH = 'birch'
@@ -63,7 +63,7 @@ class PollenName(Enum):
     OAK = 'oak'
 
 
-class PollenLevel(Enum):
+class PollenLevel(StrEnum):
     """Possible pollen levels"""
 
     NONE = 'none'
@@ -74,7 +74,7 @@ class PollenLevel(Enum):
     RED = 'red'
     PURPLE = 'purple'
 
-class WarningType(Enum):
+class WarningType(StrEnum):
     """Possible warning types"""
 
     COLD = 'cold'
diff --git a/tests/conftest.py b/tests/conftest.py
index ee69c08..f335085 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -21,3 +21,15 @@ def get_api_with_data(fixture: str) -> IrmKmiApiClientHa:
     api = IrmKmiApiClientHa(session=MagicMock(), user_agent='', cdt_map=IRM_KMI_TO_HA_CONDITION_MAP)
     api._api_data = get_api_data(fixture)
     return api
+
+def is_serializable(x):
+    try:
+        json.dumps(x)
+        return True
+    except (TypeError, OverflowError):
+        return False
+
+def assert_all_serializable(elements: list):
+    for element in elements:
+        for v in element.values():
+            assert is_serializable(v)
\ No newline at end of file
diff --git a/tests/test_current_weather.py b/tests/test_current_weather.py
index 5fe7c41..3beb139 100644
--- a/tests/test_current_weather.py
+++ b/tests/test_current_weather.py
@@ -5,7 +5,7 @@ import pytest
 from freezegun import freeze_time
 
 from irm_kmi_api import CurrentWeatherData
-from tests.conftest import get_api_data, get_api_with_data
+from tests.conftest import get_api_data, get_api_with_data, is_serializable
 from irm_kmi_api.const import ATTR_CONDITION_CLOUDY, ATTR_CONDITION_PARTLYCLOUDY
 
 
@@ -140,3 +140,10 @@ def test_current_weather_attributes(
         assert r == expected_
 
     run(sensor, expected)
+
+@freeze_time(datetime.fromisoformat('2023-12-26T17:30:00+00:00'))
+def test_current_weather_is_serializable() -> None:
+    api = get_api_with_data("forecast.json")
+    tz = ZoneInfo("Europe/Brussels")
+    result = api.get_current_weather(tz)
+    assert is_serializable(result)
\ No newline at end of file
diff --git a/tests/test_daily_forecast.py b/tests/test_daily_forecast.py
index da96a39..0123c93 100644
--- a/tests/test_daily_forecast.py
+++ b/tests/test_daily_forecast.py
@@ -4,7 +4,7 @@ from zoneinfo import ZoneInfo
 from freezegun import freeze_time
 
 from irm_kmi_api import ConditionEvol, ExtendedForecast
-from tests.conftest import get_api_with_data
+from tests.conftest import get_api_with_data, assert_all_serializable
 from irm_kmi_api.const import ATTR_CONDITION_PARTLYCLOUDY
 
 
@@ -106,3 +106,11 @@ async def test_sunrise_sunset_be() -> None:
 
     assert result[2]['sunrise'] == '2023-12-28T08:45:00+01:00'
     assert result[2]['sunset'] == '2023-12-28T16:43:00+01:00'
+
+
+def test_daily_serializable() -> None:
+    api = get_api_with_data("forecast.json")
+    tz = ZoneInfo("Europe/Brussels")
+
+    result = api.get_daily_forecast(tz, 'fr')
+    assert_all_serializable(result)
\ No newline at end of file
diff --git a/tests/test_hourly_forecast.py b/tests/test_hourly_forecast.py
index 929a631..74edb3d 100644
--- a/tests/test_hourly_forecast.py
+++ b/tests/test_hourly_forecast.py
@@ -4,7 +4,7 @@ from zoneinfo import ZoneInfo
 from freezegun import freeze_time
 
 from irm_kmi_api import Forecast
-from tests.conftest import get_api_with_data
+from tests.conftest import get_api_with_data, assert_all_serializable
 from irm_kmi_api.const import ATTR_CONDITION_CLOUDY, ATTR_CONDITION_RAINY
 
 
@@ -88,4 +88,10 @@ def test_hourly_forecast_midnight_bug() -> None:
 
     assert result[24]['datetime'] == '2024-06-01T00:00:00+02:00'
 
+def test_hourly_serializable() -> None:
+    api = get_api_with_data("forecast.json")
+    tz = ZoneInfo("Europe/Brussels")
 
+    result = api.get_hourly_forecast(tz)
+
+    assert_all_serializable(result)
diff --git a/tests/test_pollen.py b/tests/test_pollen.py
index 358b0bc..df9eefa 100644
--- a/tests/test_pollen.py
+++ b/tests/test_pollen.py
@@ -1,7 +1,7 @@
 from unittest.mock import AsyncMock
 
 from irm_kmi_api import PollenLevel, PollenName, PollenParser
-from tests.conftest import get_api_with_data, load_fixture
+from tests.conftest import get_api_with_data, load_fixture, is_serializable
 
 
 def test_svg_pollen_parsing():
@@ -76,3 +76,9 @@ async def test_pollen_data_from_api() -> None:
                 PollenName.HAZEL: PollenLevel.NONE}
     assert result == expected
 
+def test_pollen_is_serializable():
+    with open("tests/fixtures/pollens-2025.svg", "r") as file:
+        svg_data = file.read()
+    data = PollenParser(svg_data).get_pollen_data()
+
+    assert is_serializable(data)
\ No newline at end of file
diff --git a/tests/test_radar_forecast.py b/tests/test_radar_forecast.py
index a2085c1..7f0ebcf 100644
--- a/tests/test_radar_forecast.py
+++ b/tests/test_radar_forecast.py
@@ -1,7 +1,7 @@
 import pytest
 
 from irm_kmi_api import RadarForecast
-from tests.conftest import get_api_with_data
+from tests.conftest import get_api_with_data, assert_all_serializable
 
 
 def test_radar_forecast() -> None:
@@ -78,3 +78,10 @@ async def test_current_rainfall_unit(
 
     for r in radar_forecast:
         assert r.get('unit') == expected
+
+def test_radar_serializable() -> None:
+    api = get_api_with_data("forecast.json")
+
+    result = api.get_radar_forecast()
+
+    assert_all_serializable(result)
\ No newline at end of file
diff --git a/tests/test_warning.py b/tests/test_warning.py
index 4e0c939..41435ad 100644
--- a/tests/test_warning.py
+++ b/tests/test_warning.py
@@ -3,7 +3,7 @@ from datetime import datetime
 from freezegun import freeze_time
 
 from irm_kmi_api import WarningType
-from tests.conftest import get_api_with_data
+from tests.conftest import get_api_with_data, is_serializable
 
 
 @freeze_time(datetime.fromisoformat('2024-01-12T07:10:00+00:00'))
@@ -23,3 +23,13 @@ async def test_warning_data() -> None:
     assert first.get('friendly_name') == 'Fog'
     assert first.get('id') == 7
     assert first.get('level') == 1
+
+
+async def test_warning_data_is_serializable() -> None:
+    api = get_api_with_data("be_forecast_warning.json")
+
+    result = api.get_warnings(lang='en')
+    for r in result:
+        del r["starts_at"]
+        del r["ends_at"]
+        assert is_serializable(r)
\ No newline at end of file