I was reading back through the manual and it says the prediction is for the next 12-24 hour period with a 75% accuracy, sounds like they are having a dollar each way.
So if I'm showing a sunny day now which it is then it should be clear tonight as well
still it's all good fun.
I liked your weather website it's very well set up and very informative it actually looks similar to the one that is on the computer at the RFS station I'm with.
cheers