I have a weird problem. About three weeks ago, after it rained, I saw that my rear pass tire was totally flat. I filled it up. For three weeks, I drove it every day, no problem. Yesterday, it rained again and I saw at work that it was totally flat again. I filled it up again and took it home.

At home, I took the tire off and sprayed it with soapy solution all over (including valve stem) but couldn't see any bubbles. Now the rim is still bent in one spot on the inside, but there is no driveability issue or any apparent leak from there.

Any idea why it would happen only when it rains?

If the air is leaking out on the rim that is bent, im willing to bet that when it rains, Water gets in between the seal of the tire and rim and then loses the air. I say replace the rim or have it repaired if thats possible.

First thing that comes to mind is don't drive in the rain...

Sunny days only.

Seriously.. when the bead seats..it should seal, bent rim or not..once it'* sealed..rain shouldn't effect it.

It'* possible you have Murphy'* Law... you only need to fill it in the pouring rain.

Thanks for the chuckle. I am going to get it sealed and monitor whether the tire is leaking any air.

why not try to duplicate it, hose it down with soapy water, look for bubbles

Again?

Over the past several years, every flat I've had to change has been in the rain, too.

Have you checked the tread area for any foreign objects, or just around the seal and valve stem?

Sometimes a crack can develop in a rim that will only leak when the wheel is on the vehicle, with weight applied at a certain spot. Had that happen on a '61 Bonneville - nearly drove me nuts finding it. Could be your problem, too - the rim only leaks in a certain position and coincidentally for you - it happened to be raining both times.

Just a guess.

not off the car this time, yes, do it again under weight, duh!