nictha-

verb. to rain, hail, snow

An impersonal verb in the Gnomish Lexicon of the 1910s appearing as G. nictha “it is raining, hailing, is snowing” (GL/60), clearly based on the early root ᴱ√NIQI “white” (QL/66) with qt [kʷt] > cth [xθ].

Neo-Sindarin: If updated to Neo-Sindarin, this verb would be ᴺS. nítha- since since k spirantalized and then vocalized before th. However, I would limit its use to “snow, hail”, and for the verb “rain” I’d instead use ᴺS. uil.

ubra-

verb. to rain