caused by the weather

weather-sensitive, meteorosensitive (habitually having headaches, mood swings etc. due to changes in weather)

weather vane, weathervane

weathercock

genitive singular of Wetterchen

Diminutive of Wetter

A frog kept in a jar with a small ladder; when the frog climbed up the ladder, this was seen as an indication of warmer weather in the following days. / A meterologist, weatherman.

nominative/genitive/dative/accusative plural of Wetteraussicht

(chiefly in the plural) weather forecast (prediction about the future state of the weather)

nominative/genitive/dative/accusative plural of Wetterfühligkeit