I struggle a lot with this on cold, windy days...and especially on hills. If the temps aren't cold enough for a balaclava, then I'll wear a thin Smartwool neck gaiter that I can bring up over my nose/mouth to warm the air a bit before breathing it in. Aside from that, the only other thing I do to prevent it is to take a really good hit of my rescue inhaler right before stepping out of the house...but I assume you are already doing that.

Linda