My Van starts just fine on a sunny day but the vehicle refuses to start on rainy

What is your question?

I have taken it to the several shops and had tune up done in hopes it would resolve the issue, No luck, When it is muggy, humid and wet outside the vehicle refuses to start. I can only use it on sunny dry days. Their is no Check engine lights on and everything seems to be working like it should but when it is wet with sprinkle of water the vehicle tries to turn over but it never does. Any clues or ideas what could be causing this issue?