Car lurches left unexpectedly when it's raining?

I drive a 2005 Honda Civic, for some reason the car swerves to the left at odd times. It just seems like its out of control and almost like its fishtailing. Also, this only happens when its raining, any other time its completely fine. If anyone can tell me the reason or what I could do to fix it, it would be much appreciated. Also, my tire thread is a bit low and I've been meaning to get new ones. That might be the problem but I don't understand why it would make the car go to the left so badly

Get it checked, A sloppy idle control arm or control arm between the tie rods can do that. If it's simply the tires you'd always notice a tendency to have to hold the wheel to the right to correct. Or, it'd always drift leftward.

Bald tires can cause it, coupled with loose parts, the torque steer of a transaxle can be interacting with play or looseness.
Time to get it inspected and see what makes the list.
Hard to diagnose further if loose parts are found.
Replace those and have good tread on it before continuing the diagnosis.

Sounds like hydroplaning. If your tires are slick and worn, that is most likely the cause. You should get better tires SOON or you will be involved in an accident.

Don't drive in the rain, it sounds dangerous.

It sure sounds like hydroplaning on tires so worn they are unable to handle water standing on the road surface. Now is the time for fresh rubber, and the tire shop should also check your car's suspension for alignment, worn or loose components, which could also cause the swerving.

This really needs to be investigated by a garage.

It could be tyre treads on one side, or tyre pressures, or faulty shock absorbers, or faulty brakes, or… Well, the list goes on.

For your own safety, get it checked out soon.