When starting car it shakes and goes off after it rains and takes too long to stop shaking?

When starting car it shakes and goes off after it rains and takes too long to stop shaking?
It may be "flooding" one or more cylinders when it's damp or you may have a sparkplug wire that's arcing when the air is more humid.Try this, wait for a time when it's dark and you're pretty sure the engine will run the way you just described, then have a friend start the engine IN THE DARK while you're watching with the hood open. Look for a blue spark somewhere along the plug wires. If you see plug wire arcing, that's your problem. Replace the plug wires. If the vehicle is older, it could just be a case of low compression in a couple cylinders and it's just taking them a little while to finally catch when they're cold. An engine with low compression will always be more difficult to start.Also check the sparkplugs, but make sure you don't get the plug wires mixed up so only disconnect one plug wire at a time and pull and examine the sparkplug for damage or fouling.