I have done some car camping in the past. It inevitably rains while I am camping. I never had much trouble getting a fire started or keeping it going in the rain. I usually put up a tarp over a picnic table so there was a dry place to sit and eat, and it was not real hard to start a fire under one edge of it - usually the end away from where the wind is coming from. You might think it would damage the tarp but if it is 8 feet or so above the ground and the fire is not real large it works pretty well. Especially with a light breeze. Not that the wind cooperates all the time. It seems like sometimes the wind shifts almost continuously in both direction and intensity. I do not know how to keep a fire going in a serious downpour though without some kind of overhead cover.

A guy camped next to us one time had a piece of angled sheet metal that he set up over top of the fire pit when it rained. Looked kind of like a pitched roof over the fire. He was more or less a resident of the place though, and could afford to be a little more elaborate than us more casual campers.

Another guy that came thru one time in a bus (a very pricey bus) had some kind of flat topped "u" shaped piece of sheet metal he used for the same purpose, but I think he used it to cook on as well. Kind of like a wood cook stove.