While subterranean termites are active year-round, the peak swarm season usually begins in spring and can last into summer and fall. Drywood termites swarm between May and August. Warm temperatures coupled with rainfall can trigger periods of swarming throughout the year.
During swarming season, winged termites may appear inside a home, indicating a serious infestation has taken root. Called swarmers, these reproductive winged termites separate from their nests to form colonies of their own. They're most likely to appear in large numbers during warmer months. Unlike worker termites, swarmers are drawn to brightly lit areas and can be found near windows and doors in infested homes.