diff --git a/homeassistant/components/openweathermap/weather_update_coordinator.py b/homeassistant/components/openweathermap/weather_update_coordinator.py
index db8c48aeac4..5c2633a7a33 100644
--- a/homeassistant/components/openweathermap/weather_update_coordinator.py
+++ b/homeassistant/components/openweathermap/weather_update_coordinator.py
@@ -18,10 +18,10 @@ from homeassistant.components.weather import (
     ATTR_FORECAST_WIND_BEARING,
     ATTR_FORECAST_WIND_SPEED,
 )
-from homeassistant.const import TEMP_CELSIUS
 from homeassistant.helpers import sun
 from homeassistant.helpers.update_coordinator import DataUpdateCoordinator, UpdateFailed
 from homeassistant.util import dt
+from homeassistant.util.temperature import kelvin_to_celsius
 
 from .const import (
     ATTR_API_CLOUDS,
@@ -180,10 +180,10 @@ class WeatherUpdateCoordinator(DataUpdateCoordinator):
 
         return forecast
 
-    def _fmt_dewpoint(self, dewpoint):
+    @staticmethod
+    def _fmt_dewpoint(dewpoint):
         if dewpoint is not None:
-            dewpoint = dewpoint - 273.15
-            return round(self.hass.config.units.temperature(dewpoint, TEMP_CELSIUS), 1)
+            return round(kelvin_to_celsius(dewpoint), 1)
         return None
 
     @staticmethod