San Diego mostly stays sunny year round. In the summer, spring, and fall months you can expect to be wearing clothing to stay cool. This means bikinis & boardshorts are what most people will be wearing to the beaches in these months, where whether can range from 60-90° F. On colder days such as in the winter months a jacket and possibly a blanket are a must for San Diego beaches! In the colder winter months expect the temperature to range from 45-75° F.