Proto-Indo-European Roots

Root/Stem: *g'heim-
Meaning:  cold, winter
Hellenic Greek kheimón 'winter'
Italic Latin hiems 'winter'
Celtic Common Celtic *gimo-, *gaimo- >
Irish geimhreadh, Early Irish gemred, Old Irish gam, gaimred, Old Welsh gaem, Welsh gauaf, Old Cornish goyf, Breton goam, Middle Breton gouaff, Gaulish Giamillus (a name)
Indic Sanskrit hima- 'cold', heman 'in winter'
Iranian Avestan zima- 'winter'
Persian dai < *gheimen 'winter'
Anatolian Hittite gima- 'winter'
Armenian Armenian giun 'winter', gen. gean
Balkan Albanian dimër 'winter', gen. dimri
Germanic Common Germanic *gim- 'winter, year' >
Old Norse góimánaðr 'a winter month', Icelandic goa, Norwegian gjö, Swedish göjemanad, Danish gimmer- 'a year old'
Baltic Common Baltic *z'iema 'winter'>
Lithuanian z'iema 'winter', Latvian ziema, Old Prussian semo 'winter', seamis 'winter corn'
Slavic Common Slavic *zima 'winter' >
Russian & Ukrainian & Bulgarian & Polish & Slovene & Czech zima, Sorbian zyma
Notes: Quite a stable root which obviously denoted 'winter' already in the Proto-language. Though the majority of linguists agree that Proto-Indo-Europeans used to live in hot climate, they were acquainted with snow and winter, as linguistic materials show.