for me there's two types of rain.
rain you can work in and rain you can't.
basically i would work in fine rain, basically the type where you'd have intermintent wind screen wipers on van.
you should base your work on a four day week.
i have a must earn wage, which i nearly always earn, as said because my works based over 4 days.( x amount a week/ 4 days) once this is reached, i still keep going.
some weeks i work 6 days (saturdays 10.30ish til say 2pm)
I just keep going while weathers o.k but never work sundays!
you never know what's around the corner i lost a weeks work in feb due to snow.
I see w/c's out there on ladders in snow-ice

my mrs friend went out in snow on day 1 slipped over broke her ankle, didn't set right, still off work now.

It's all about getting price's right, but this will be determined by where you live.
I charge £12 average for 3 bed semi, but have heard others do the same for £6 or less
when you first start you'l under price, can't be helped

you need to sit down and do some number crunching with the calculator.
I've been given advice by others that i found to be true always charge a third more than you want to earn an hour as there is alot of time lost in van/car to-ing and thro-ing.
I'd say the ave is £20 an hour, but this will be determined as said on location; prices.
if you can't achieve this rate running a monthly round then extend the clean date out to allow room to charge more i.e 6 weeks or 8 weeks(max) this will only really work if your wfp (imo)
sorry i've rambled on.
I don't work in rain because (IMO) custy's don't like it
i don't like getting wet if i was honest.
but some on here do work in rain up to you

It's not how many days you work; but how much you earn in the days you do

good luck mate