diff --git a/homeassistant/components/weather/openweathermap.py b/homeassistant/components/weather/openweathermap.py
index 00d9bc47f1b..46a0b3ecc14 100644
--- a/homeassistant/components/weather/openweathermap.py
+++ b/homeassistant/components/weather/openweathermap.py
@@ -173,7 +173,10 @@ class OpenWeatherMapWeather(WeatherEntity):
                     ATTR_FORECAST_TEMP:
                         entry.get_temperature('celsius').get('temp'),
                     ATTR_FORECAST_PRECIPITATION:
-                        entry.get_rain().get('3h'),
+                        (round(entry.get_rain().get('3h'), 1)
+                         if entry.get_rain().get('3h') is not None
+                         and (round(entry.get_rain().get('3h'), 1) > 0)
+                         else None),
                     ATTR_FORECAST_CONDITION:
                         [k for k, v in CONDITION_CLASSES.items()
                          if entry.get_weather_code() in v][0]