Yeah, originally there was supposed to be acid rain and other dangerous weather effects. That got cut. As did the AI entirely, which is why NPC's don't react to anything as they should.
There still is acid rain actually but its only a visual rain effect. It comes with the insanely brown/foggy weather but is very very rare, i've only seen it once in over 120h+
regular rain like in the pictures happens more often but still way too little in my opinion :/
Probably some developer has already gone through that problem, if your machine does not give enough horsepower it is better not to rain during the process so that the engine does not fluI have no idea what's going on with my version. It's rained when you meet the detective, and when Jackie picks you up, but I've never seen it rain outside of those two missions. The ground will get wet but I see no rain effects when this happens. I think there's some kind of bug.
These can also happen, the machine goes in 4th, high revs and reaches 5th with the reflexes but since you don't have 6th or your car is automatic it will not give you anything else xD