Termites are most active and primarily swarm in California during the spring, summer, and sometimes autumn. Specifics will depend on your location in California and the type of termites you’re experiencing. While warmer-weather months are the most conducive for termite swarms, termites are sometimes also active during colder months when they are living in heated spaces. Termites in California also have the benefit of enjoying the generally warm regional climate, so are often considered to be year-round pests.