*ḏVnVm-/ḏVnVn- - rain (DRS 336; Kogan 2011: 193–194)

Probably *ḏnn is the original shape of the root dissimilated in EthS and Sab, but the reverse possibility (an original *ḏnm assimilated to znn in Akkadian) cannot be excluded either (cf. DRS 336) (Kogan 2015: 442-443)

Akkadian

zanānu - to rain (CAD Z 41, AHw. 1509)

Cf. zunnu ‘rain’ (AHw. 1537).

Ebla

ša-na-mu-mu /ḏanāmum/ - to rain (VE 1403′, Kogan–Krebernik 2021b: 690)

Hebrew

zäräm - rain (HALOT 281)

may be related with dissimilation

Sabaic

ḏnm - rain (SD 39)