Very typical question :) For some reason many foreigners are convinced that in Russia there's always snow and cold - and it's sometimes quite hard to convince them that in summer it's usually hotter than in most of European countries. BTW another typical question - "what is the weather in Russia now"? ;)
Well, if we consider coastal Sochi rather than mountains, the temperature there was +10..20 Celsius during the Olympics ;-) In fact, the main aim of those Olympics was to popularize Sochi as a winter resort as well as a summer one - and so far it seems to go well enough, at least past New Year holidays recorded as many people in Sochi as during the peak of summer season.
But it's true that in many Russian regions it's very cold in this time of year: e.g. in Yakutia might well be -50 (however in that same region it's +30..35 in summer).
Anyway, I think I've got your point - to change people's opinion we now need to organize Summer Olympics in Saint-Petersburg which used to be the north-most world capital a century ago :-)