Same word as rain:

cat-and-dog weather, cloudburst, condensation, deluge, drencher, drizzle, fall, flood, flurry, hail, heavy dew, liquid sunshine, mist, monsoon, pour, pouring, precip, precipitation, raindrops, rainfall, rainstorm, sheets, shower, showers, sleet, spate, spit, sprinkle, sprinkling, stream, sun shower, torrent, volley, wet stuff, window washer