I use OpenWeatherMap in weather binding. Here’s what it’s sending. I believe there’s rain precipitation values larger 0 (if it’s gonna rain, but we’re lucky these days over here in Germany).
2018-06-07 17:30:23.361 [DEBUG] [nal.provider.AbstractWeatherProvider] - OPENWEATHERMAP[home]: Weather[Temperature[current=28.67,min=28.0,max=29.0,feel=30.739108113728843,dewpoint=<null>],Atmosphere[humidity=35,visibility=<null>,pressure=1014.0,pressureTrend=down,ozone=<null>,uvIndex=<null>],Clouds[percent=0],Condition[text=Klarer Himmel,lastUpdate=Thu Jun 07 17:30:23 CEST 2018,observationTime=Thu Jun 07 16:50:00 CEST 2018,id=800,icon=01d,commonId=sunny],Precipitation[rain=0.0,snow=0.0,probability=<null>,total=<null>],Wind[speed=9.359999992512002,direction=NNE,degree=20,gust=<null>,chill=<null>],Station[name=Paderborn,id=<null>,latitude=51.7191,longitude=8.7544,altitude=<null>],<null>]
2018-06-07 17:30:23.366 [DEBUG] [nal.provider.AbstractWeatherProvider] - OPENWEATHERMAP[home]: Forecast[day=0,Temperature[current=<null>,min=18.2,max=27.01,feel=<null>,dewpoint=<null>],Atmosphere[humidity=70,visibility=<null>,pressure=996.03,pressureTrend=<null>,ozone=<null>,uvIndex=<null>],Clouds[percent=20],Condition[text=Ein paar Wolken,lastUpdate=Thu Jun 07 17:30:23 CEST 2018,observationTime=Thu Jun 07 13:00:00 CEST 2018,id=801,icon=02d,commonId=partly-cloudy-day],Precipitation[rain=0.0,snow=0.0,probability=<null>,total=<null>],Wind[speed=7.9919999936064015,direction=SSE,degree=151,gust=<null>,chill=<null>],Station[name=<null>,id=<null>,latitude=<null>,longitude=<null>,altitude=<null>],<null>]
2018-06-07 17:30:23.370 [DEBUG] [nal.provider.AbstractWeatherProvider] - OPENWEATHERMAP[home]: Forecast[day=1,Temperature[current=<null>,min=17.02,max=25.54,feel=<null>,dewpoint=<null>],Atmosphere[humidity=75,visibility=<null>,pressure=995.02,pressureTrend=<null>,ozone=<null>,uvIndex=<null>],Clouds[percent=20],Condition[text=Ein paar Wolken,lastUpdate=Thu Jun 07 17:30:23 CEST 2018,observationTime=Fri Jun 08 13:00:00 CEST 2018,id=801,icon=02d,commonId=partly-cloudy-day],Precipitation[rain=0.0,snow=0.0,probability=<null>,total=<null>],Wind[speed=9.539999992368001,direction=E,degree=81,gust=<null>,chill=<null>],Station[name=<null>,id=<null>,latitude=<null>,longitude=<null>,altitude=<null>],<null>]
2018-06-07 17:30:23.374 [DEBUG] [nal.provider.AbstractWeatherProvider] - OPENWEATHERMAP[home]: Forecast[day=2,Temperature[current=<null>,min=17.86,max=25.23,feel=<null>,dewpoint=<null>],Atmosphere[humidity=75,visibility=<null>,pressure=994.32,pressureTrend=<null>,ozone=<null>,uvIndex=<null>],Clouds[percent=8],Condition[text=Klarer Himmel,lastUpdate=Thu Jun 07 17:30:23 CEST 2018,observationTime=Sat Jun 09 13:00:00 CEST 2018,id=800,icon=02d,commonId=sunny],Precipitation[rain=0.0,snow=0.0,probability=<null>,total=<null>],Wind[speed=9.5759999923392,direction=ENE,degree=58,gust=<null>,chill=<null>],Station[name=<null>,id=<null>,latitude=<null>,longitude=<null>,altitude=<null>],<null>]
2018-06-07 17:30:23.378 [DEBUG] [nal.provider.AbstractWeatherProvider] - OPENWEATHERMAP[home]: Forecast[day=3,Temperature[current=<null>,min=16.31,max=25.28,feel=<null>,dewpoint=<null>],Atmosphere[humidity=78,visibility=<null>,pressure=991.13,pressureTrend=<null>,ozone=<null>,uvIndex=<null>],Clouds[percent=68],Condition[text=Mäßiger Regen,lastUpdate=Thu Jun 07 17:30:23 CEST 2018,observationTime=Sun Jun 10 13:00:00 CEST 2018,id=501,icon=10d,commonId=few-showers],Precipitation[rain=7.77,snow=0.0,probability=<null>,total=<null>],Wind[speed=7.9559999936352,direction=SW,degree=217,gust=<null>,chill=<null>],Station[name=<null>,id=<null>,latitude=<null>,longitude=<null>,altitude=<null>],<null>]
2018-06-07 17:30:23.388 [DEBUG] [nal.provider.AbstractWeatherProvider] - OPENWEATHERMAP[home]: Forecast[day=4,Temperature[current=<null>,min=14.66,max=20.96,feel=<null>,dewpoint=<null>],Atmosphere[humidity=0,visibility=<null>,pressure=1005.66,pressureTrend=<null>,ozone=<null>,uvIndex=<null>],Clouds[percent=60],Condition[text=Starker Regen,lastUpdate=Thu Jun 07 17:30:23 CEST 2018,observationTime=Mon Jun 11 13:00:00 CEST 2018,id=502,icon=10d,commonId=rain],Precipitation[rain=21.29,snow=0.0,probability=<null>,total=<null>],Wind[speed=10.691999991446401,direction=NE,degree=49,gust=<null>,chill=<null>],Station[name=<null>,id=<null>,latitude=<null>,longitude=<null>,altitude=<null>],<null>]