You could could keep washing in those temps but, the problem is, even in those temps most people can care less about having their property washed. It’s just not on their mind because they aren’t outside as much so they don’t see it. At least that’s my thoughts on it. I’m not in a milder climate like you so you’ll get better advice from others who are.
I would think that if you’re mainly going to be washing in winter you might want to look into commercial. Although, it’s going to take a lot more startup costs partly due to needing a hot water machine. Getting commercial jobs isn’t going to happen overnight so I wouldn’t count on it this winter. If you advertise correctly you’ll get some calling you but you really have to go to them and sell yourself. That means getting some shirts made up, business cards, etc. You should be getting that stuff anyways even if you’re just sticking to residential.
If you do decide to go forward do things the right way and price accordingly. You don’t want to be that hack who comes out the gate with a little homeowner pressure washer, no insurance, and washing houses for $100. That drives down the price for every contractor in the area. Do things the right way, research and wash the right way, and you can demand higher prices.
Just so you know when washing it’s not about the pressure it’s about using the proper chemicals. High pressure should never be used on houses, decks, fences, roofs, and a lot of other stuff. Here are some search terms to research on here to get you going.
house wash mix
Take notes or bookmark the important pages. Start reading and you’ll learn answers to questions you didn’t even know you had yet. Pressure washing isn’t rocket science but there’s more to it than what you think or at least when you’re just jumping in.