One of the oddities of
vaping is that it isn't compatible cold weather at all. Many times over the previous 2 winters I have noticed
vaping is near impossible, but never had to give up yet.
-10 Celsius is where the consistency of my juice changed enough to make a drip tip totally useless, lol, so I just remove/ replace my drip tip instead (Note this has to be a 510. I found 306 drip tips would lock VERY easily in the cold... and blowing into it isn't going to help at that point)
Best advice I can give is to keep your juice as warm as possible, preferably in your hand or in a pocket that isn't as exposed to the elements. Otherwise you will have a very thick juice in need of a hot water bath on the coldest days.
Stealth vaping in the bathroom is another great option and keeps you, your juice and your poor battery out of the coldest weather.