California pest season calendar
California's pests track its wet winters and dry summers. These windows come from the University of California Statewide IPM Program.
| Pest | Peak window | What it means for you | Source |
|---|---|---|---|
| Subterranean termites | after fall or spring rains | Native subterranean termites tend to swarm on warm days following fall or spring rains, so watch for winged insects after the first rains. | UC Statewide IPM Program |
| Drywood termites | summer and fall | Drywood termite swarmers most often appear during daytime in summer and fall. They are most common in southern California and along the coast. | UC Statewide IPM Program |
| Argentine ants | year-round, more indoors in winter | The Argentine ant is the most common house ant in California. It often moves indoors during winter to escape flooding or cold, and sweet baits stay effective year-round. | UC Statewide IPM Program |
| Formosan termites | late May through early August | Where the Formosan subterranean termite is established in California, its swarming season runs from about late May through early August. | UC Statewide IPM Program |
Windows are general guidance from the cited university extension and state sources, checked on 2026-07-19. Local weather and microclimate shift them, so treat these as planning ranges rather than exact dates.
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