My car is always doing things like this in wet weather - but soon reverts back to normal -'firing on two cylinders' (whatever that means - and incidentally only has 3 just in case you think it should have 4)
I had to lift the bonnet this morning - I think thats the first time I've done it in the 8 years I've had the car, batteries don't last forever - I had to get a new one today but needed a jump start to get to the garage