If u pay close attention it does tell u..
on the left u have the track conditions, theres a little bar if that is empty then theres no water on track if the bar is half full or full it means there water in places or all around the track, also the cloud in the track section state if it is raining how hard and what kinda rain is falling at that time.
then u got the section next to it the sky section showing u what is predicted for the rest of the race..
its a little confusing but does tell u whats going on but u gotta pay attention coz it may state the track maybe wet but everything else is sunny or vice verser where the track is dry but has just started raining soo yeah