I know the feeling!
I borrowed next door's jet-washer to get the pollen off my Z4 and daily on Friday, then got carried away and hand-washed them both.
So sure enough it rained on Saturday and left some dust - then when I was coming home on Sunday at around 6pm I got caught in a snow-storm. :?
No wonder I don't do it too often! As they both live outdoors it just seems a bit pointless. :lol: