Our car interminately does not start after a nightfall heavy rain or high humidity and dew point in first thing in the morning.The car starts fine at all other points of the day.

I take it, it turns over ok.Spray the ignition wires with WD-40,that's a water displacer. If it starts ok then, replace the wires. If still no start then spray the distributor cap. It may have a crack in it (that you can't even see). If there's moisture inside the cap, you've found it.Finally try spraying the ignition coil tower ( where the big wire comes out). That can be cracked too.