Termite Swarm Season 2026: When Termites Swarm in Every State

It sweeps north with the warmth: Florida and the Gulf Coast see the first subterranean swarms in late January and February, the mid-South and Mid-Atlantic in March and April, the Northeast and upper Midwest in May and early June. Formosan termites fly at dusk from late April through June across the Gulf states; drywood and dampwood termites fly on warm late-summer and fall evenings in the West. The table on this page lists every state's window and today's status.

Eastern, western, and arid-land subterranean termites fly in daylight — usually late morning to mid-afternoon on the first warm, humid, calm day after rain. Formosan and Asian subterranean termites fly at dusk and into the night, and they pile up under porch lights and streetlights. Drywood and dampwood termites fly on warm evenings. Desert subterranean termites, in southern Arizona and southeastern California, fly at night after monsoon storms.

Swarmers come from a mature colony at least three to five years old, so yes — a colony is nearby. Swarmers emerging indoors (from a wall, window frame, or baseboard) almost always mean the colony is in or under the house. Swarmers outdoors mean a colony within a few hundred feet, which may or may not include your home. Either way: collect a few, book an inspection, and do not sign a treatment contract the same day.

Termite swarmers have straight, beaded antennae, a broad waist with no pinch, and two pairs of wings of equal length about twice as long as the body. Flying ants have elbowed antennae, a narrow pinched waist, and front wings longer than the hind wings. Termite wings also detach easily — piles of identical shed wings are a termite tell.

Nationally, a liquid barrier treatment for a typical home runs about $1,200–$3,500 (roughly $3–$16 per linear foot of foundation); bait systems $1,500–$3,500 installed plus $300–$500 a year for monitoring; whole-structure fumigation for drywood termites $2,000–$8,000+ depending on the cubic footage of the house; localized drywood spot treatments $300–$1,500. Formosan work costs more. Every state page here gives a state-specific range and a link to the extension service's impartial guidance.

Some do. Formosan and Asian subterranean termites (Gulf Coast, Florida, Hawaii) and most drywood termites fly at dusk or at night and are strongly attracted to lights. The native eastern and western subterranean termites — the most common species in most states — fly in daylight after rain.

The International Residential Code includes a Termite Infestation Probability Map (Figure R301.2(7) in the 2021 edition; the figure number moves between editions), built on US Forest Service survey data, that divides the country into four bands: very heavy — the Gulf and Deep South plus nearly all of California; moderate to heavy — most of the rest of the southern and central US, the desert Southwest and the Mid-Atlantic included; slight to moderate — the northern tier, Rockies, and Pacific Northwest; and none to slight. The figure labels those bands by name rather than numbering them, so the zone I–IV shorthand used on this site is ours, not the code's. Where a local jurisdiction designates an area as subject to termite damage, new construction must include protection — soil termiticide, a baiting system, pressure-treated or naturally durable wood, a physical barrier, or steel framing. The map's own note warns the lines are approximate and local conditions may be more or less severe than the band suggests.

Vacuum the swarmers and bag a dozen for identification, note exactly where they came out, and schedule a licensed inspection within a week or two. Don't spray — swarmers die within hours anyway, and spraying erases the evidence. Be especially skeptical of door-to-door offers and "today only" pricing in the days after a big swarm; get two written bids, check license numbers with your state regulator, and never pay in full up front.