'97 Tahoe won't start when wet

I have a 97 Tahoe that has trouble starting if it has been sitting for an extended amount of time (15+ hours) while it is raining/damp out. It turns and turns but won't fire. Then, after it dries up, it starts right up.

Any ideas? Do you need more info?

Thanks for your help.

Might be time for a new distributor cap and rotor

Had this issue on a same year chevy pickup. Check/replace coil and wiring (don't forget spark plug wiring, too)...one or both are letting moisture in somewhere.

thanks for your help....