I do, just mostly easy trails so I'm not sure it would count as real mountainbiking but it's more for exersice then sport. Currently ride a Scott bike, really good bikes!
Haven't been out in the winter with this bike but I used to almost everyday during the winters and it's really refreshing and it's not that cold as long as you push and get your body heat up. Also the best with biking in the winter is that there are no flies that tries to make you eat them
The coldest I've biked through is -31 one morning but it was a bit too cold haha And the only time I've experienced temps that low around here, the lowest is usually around -25 and thats rarly that cold during the day usually never lower then -20 during the day and usually around -10 so you defenetly have it colder where you are Ath!
By the way, can reccomend Alexrims, the type I have works great for both bulky MBT tires and thin racing tires, so one set of rims for two different types of riding, racing and MBT
My bike:
