diff --git a/homeassistant/components/openweathermap/weather_update_coordinator.py b/homeassistant/components/openweathermap/weather_update_coordinator.py
index 51e475eb754..20cc71da725 100644
--- a/homeassistant/components/openweathermap/weather_update_coordinator.py
+++ b/homeassistant/components/openweathermap/weather_update_coordinator.py
@@ -122,7 +122,7 @@ class WeatherUpdateCoordinator(DataUpdateCoordinator):
             ATTR_API_FEELS_LIKE_TEMPERATURE: current_weather.temperature("celsius").get(
                 "feels_like"
             ),
-            ATTR_API_DEW_POINT: (round(current_weather.dewpoint / 100, 1)),
+            ATTR_API_DEW_POINT: self._fmt_dewpoint(current_weather.dewpoint),
             ATTR_API_PRESSURE: current_weather.pressure.get("press"),
             ATTR_API_HUMIDITY: current_weather.humidity,
             ATTR_API_WIND_BEARING: current_weather.wind().get("deg"),
@@ -178,6 +178,12 @@ class WeatherUpdateCoordinator(DataUpdateCoordinator):
 
         return forecast
 
+    @staticmethod
+    def _fmt_dewpoint(dewpoint):
+        if dewpoint is not None:
+            return round(dewpoint / 100, 1)
+        return None
+
     @staticmethod
     def _get_rain(rain):
         """Get rain data from weather data."""