My weather experience so far is :
Rain ( whatever type is ) never starts before the first 1.5 laps .
Usually starts at end of lap two or starting 3 and that depends the car , if it's fast or not.
Fast cars under 4.00 minutes lap is very different to a car that lap around 4.20 , the first will meet rain at lap 3 , the second at end of lap two for example.
Of course can start later even at lap 6 which is rare but happens.
The type of rain varies a lot , might rain one time , two times or rain for 2-3 laps in a row which also is rare.
Nothing ensure dry track after rain , i faced mid race light rain that keep humidity on the track almost at the first line till the end of 7th lap.
Weather can change very fast and sometimes very slow .
Radar that shows " Doom " ( green, yellow, blue all over ) might not affect the track so hard as it shows.
Radar that have few blue spots its possible to bring " Doom " .
Many times when you think,ok its over now ..... a second wave appears and you start the .....here we go again 😂
Direction of weather also varies, can be from right to left or the opposite, up to down or the opposite and a combination of those which also is rare too .
I never had rain on lap 7 in a dry or almost dry race .
Sudden rain at end of lap 5 or starting lap 6 may occurs ( very rare ) that might keep the track wet till the end of lap 7 which i usually skip.
If rain caught the AI after pits , is a good indication for 6 lap race .
Sometimes one from the AI make the right choice and moving faster than the others in rainy track.
Other times are two groups spinning all over or one group together that hit one the other. Other times the first group moving faster while the second shows arrows turning around.
That's all from me , am continue keep notes but not with many details.
Usually i make one run per day since i start CE's and don't have time for more unless i need to test some car and skip CE's .
Have a good day guys.