I just did a 50 minute test session and the race is going to be awesome
However, I'm concerned about the rate of the weather change. I was driving on a completely dry track and when I reached the chicane near the end of the lap it started to rain and by the time I reached the first corner on the next lap the track was 100% wet. If that happens while you're in slicks you can easily be lapped by a car on wet tyres before you get a chance to change tyres.
There's always a chance element in racing, but perhaps it's too big here? You could lose the race simply by being on the wrong part of the track when it starts to rain and the only way to avoid that would be to guess when the rain is going to come and go to the pits right before that.
Also, with the weather change set to 60 the track gets completely dry almost instantly after the rain has stopped so there's not much use for intermediates.
Perhaps we could reduce the weather change a little, to about 20 or 10 or something like that? That will give you some time to go into the pits before the track is completely flooded, and the track will also stay wet for a longer period of time after the rain has ended.
One more thing, here's a driving tip that I learned during my test session: When it's 100% wet on the track, don't coast around corners in 1st gear since the engine braking is more than enough to make the rear tyres skid. Use a higher gear (2nd is usually enough) or give a little bit of throttle while you go around the corner