संस्कृत शब्दों वायु और आर्द्र से बना यूरोपियन शब्द वेदर (मौसम) Weather from Sanskrit words vayu (air) and aardra (humidity)

कुछ प्रासंगिक नोट्स-- 
आर्द्र नमीं या गीलेपन के लिए एक प्राचीन संस्कृत शब्द है। आर्द्र से ही आर्द्रता और शतद्रु बने हैं। आर्द्रता ArdratA, आर्द्रत्व Ardratva = नमी, गीलापन, moisture, wetness; और शतद्रू (शत + आर्द्रु ) ऋग्वेद में मिलता है। अर्थ है 'सौ धाराओं में बहने वाली यानी शतद्रु नदी जिसका आधुनिक नाम सतलुज है। 
शतद्रु > शतदलु > शतलुद > सतलुज 

Additional notes: 
Aardra and aardrataa are ancient Sanskrit word that mean humidity, wetness. 
Shatadru (< shat, ie. hundred + aardra) is the ancient name of the river Satluj.   

However according to dictionary.com Word Origin and History for weather  

n. Old English weder, from Proto-Germanic *wedran (cf. Old Saxon wedar,Old Norse veðr, Old Frisian, Middle Dutch, Dutch weder, Old High Germanwetar, German Wetter "storm, wind, weather"), from PIE *we-dhro-,"weather," from root *we- "to blow" (see wind (n.)). Spelling with -th- firstappeared 15c., though pronunciation may be much older.
Weather-beaten is from 1520s. Under the weather "indisposed" is from1827. Greek had words for "good weather" ( aithria, eudia) and words for"storm" and "winter," but no generic word for "weather" until kairos(literally "time") began to be used as such in Byzantine times. Latintempestas "weather" (see tempest ) also originally meant "time;" andwords for "time" also came to mean weather in Irish ( aimsir), Serbo-Croatian ( vrijeme), Polish ( czas), etc.