Definitely, yes. I doubt many people in Russia would be familiar with the Farenheit scale :) In the UK I think most people can still use it, though I tend to use a mixture of imperial and metric measures. Anyway yes, this is Celsius.
Sure they would, e.g. on a weather report, for example. The "temperature" can be skipped in either language, but since it's there in the Russian sentence, it should also be present in the English translation.