Considering that they actually included pictures from yakutsk by the same photographer (http://www.dailymail.co.uk/news/article-2548176/Feeling-cold...) It seems like they really took the time to cross all their i's and dot all their t's.

Also as someone who's grown up in winters that regularily hit -40 and -50, it can't have been that cold otherwise you wouldn't have pictures of people without a toque on, or a scarf/neckwarmer.