DiRT Rally 2.0

I got this easily by the below method.

Custom Championship
Add Event - Hell Norway (Rally Cross)
Format - Single Race
Vehicle Class - Anything (I chose RX Supercars 2019)
Weather - Daytime / Heavy Rain / Wet Surface (Heavy Rain is the key here)
Laps - 2

Confirm, then press to change championship settings, set AI performance to Very Easy if required.... Apply it and Start Championship, chose a car then win the race, be sure to make 1 of the 2 laps a joker lap.

Cheev pops during the results screens.

You don't need the dlc to get this achievement. I was just playing FIA World Rally Cross Championship and it unlocked in hell when it was raining