Up here there are arguably 6 months where interior painting is the only course. There are major headaches involved with that as well. Folks don't want the trades traipsing in and out their front or back doors with muddy/wet/snowy boots, especially when the temps go below 0. So many of them wait til the exterior season is in full swing...
The usual pattern for interior paint jobs up here is thus; gather up materials/tools/equipment from warm storage (in my case the basement), haul them up and out to the truck, transport to the job, make however many trips it takes to get EVERYTHING into the jobsite so nothing freezes (can't leave anything outside), every trip entails removing of boots/shoes to get said materials out of the entry area, then repeat...
...When the job is done, or tools and materials not needed are taken back to the shop, they must be hauled back to warm storage
immediately...No, not complaining, I need the excercise, but there is a time variant that adds significantly to the day, and subtracts significantly from any production getting done--The days wind up to be much longer than usual...