When it rains, does water pour onto the pool pump motor from the roof overhang, or, does the pool motor sit in a puddle of water? Do you have a sprinkler system that sprays water onto the pump area? If so, the chances of it shorting out are increased dramatically. If the pool motor sits in a pool of water after a rain, some sort of drainage system around it is a must. In harsh weather climates, build or buy a housing that can be put over the motor during winter. An in- expensive pool pump motor cover does a fair job of keeping rain water off the pool motor.