Ok what if you clean in the sunny day time and it rains the next day do your customers ask for their money back? nope
No they don't, you're right. They accept that as an occupational hazzard. Even if it rains later the same day, they accept it, grudgingly.
But, no, they do not accept me turning up when it is raining, to clean their windows. I can give them all the arguments I've read on here and more. They are not convinced, they hear it as sales garbage, give me that sarcastic look and say, "no thanks, not today". I can shoot them a line about how it's my business, they'll be clean when it's stopped raining, I can't keep customers that pick and choose etc. They say, "Well I don't want them done in the rain!" I don't have as much choice as some of you. Be glad if you live in a rich area where you can dictate to your customers such things, but don't make the mistake of thinking it's because you are such a good salesman. It is just the wealth of the area you live in. Or it's Scotland.

A friend of mine worked in an area of Scotland for a while, rain, rain, rain! If people wanted their widows cleaned, they had to accept they would be cleaned in the rain!
But what I charge £10 for he was getting £5!