Moisture is disrupting something in the electrical system. As stated by joseph spark plug wires are a great place to look. Make sure all connections are secure, no wires have come loose with no cracked rubber, check also the coil and clean connections if necessary. In the old days if you tried to start it in the dark you could see a stray spark of even hear a spark going to ground instead of where it is supposed to go. The sound you hear is hopefully related to the starting problem, but after you get problem 1 fixed you can see if there is a problem 2.