Working in the rain is a bit of a tricky one if you ask me. On the one hand you want to be working as you want to be earning, obviously, but on the other hand, commercial work aside, a lot of householders think you're mad cleaning their windows in the rain and I do think they have a point.
The windows on the estate I live on were cleaned a day or two before the last bout of bad weather; HEAVY rain and howling winds. The day after I looked out of my bedroom window and the windows looked terrible, as though they'd not been cleaned at all. I assume the rest of the estate looked the same, though not one of our customers told me so. Maybe they're just too polite
So, I just leave it to the customer; if they're happy with their windows being cleaned in the rain so am I, if not we leave them 'til the month after