It's the magnetic ballast that cause the trouble in cold weather..
I'm in the process of upgrading my shop to the new cold weather electronic
ballasts that are suppose to work fine down to 0 degree..
I have/had 7 magnetic 2 bulb 48" in my unheated work shop and intially some
would work in cold weather but after about 7 years, I only had 2 bulbs left
working of the 14..
Admittedly these were the cheap shop fixtures but now, for about the same
price I can get a T8 48" two bulb electronic at Home Depot.. The bulbs are
different than the the old T12s but not that much..
My opinion and experience. FWIW