you stopped what you were doing and went and cleaned them!

Dump the cheeky so and so.
You are the boss and you call the shots.
You are in a luxury position of being able to hand pick your customer base and drop all the arrogant, late paying, look down their nose, rude types.
When she sees you cleaning all the other windows in the area, she will be gutted.
Then, if she asks, you can explain that you clean when you decide, dependant on weather conditions. You WILL try and keep to a schedule as you always did but if the weather stops you working you will obviously be delayed. If you have a 2 week holiday, you will be 2 weeks late etc etc.
When she asks to be put back on your round, either tell her it has gone up a couple of quid or better still tell her she has been replaced and you are full to the limits.