WOW!! I look at a good many of forum members racing in lower performance rated cars, and being competitive with AIs of Mercedes, Ferraris, and Red Bull at Difficulty 100+, come rain or shine. Power to your elbows!!
Anyway, when I encounter wet races, I'm screwed. Okay, so I'm in a Williams.....BUT.....at Hockenheim I experienced a full wet race, and I was lapped twice by my teammate as if he, and rest of AI are on slicks in a dry race? Yet in dry conditions I have got the beating of him, hands down. So come Qualifying, or Race conditions when there's a chance of rain, I know I will suddenly become a tortoise when wet conditions come along. Grrrrrrr!!
I think when Patch 1.6 was released, there was something said about AIs wouldn't be as slow as they were then in wet conditions (just right for me before that release), but now they are seemingly jet propelled in the wet.
PAD - on PS4
Traction - Full (when I know wet conditions apply at some stage of the race)
AI Difficulty - A moderate 75 for me
Career mode at 100% race