Well I was slightly optimistic that I wouldn't need to wear a mask when doing my Christmas shopping. I can't imagine standing in a queue in the freezing cold waiting to go into the shops.
I should imagine it's better wearing one in the cold weather than in this heat. At least it should keep your nose warm. Must be awful in the pouring rain though.
I haven't worn one at all but I keep one in my pocket in case I'm challenged by the feds at any time. In fact, I've had it my pocket since April. Must get value for money.