Wet and humid weather can cause moisture in motor windings. If the windings are cracked from age, the result could be motor winding failure. For motors less than 125-Horsepower, it is usually more cost-effective to replace rather than re-wind the motor. Have your pump or motor contractor do the math to calculate payback on a new high efficiency motor versus the old inefficient one.
General Pump Company has facilities and capabilities to repair motors from 5hp to 1000hp.