Ant Season 2027: When Ants Come Indoors, State by State

Spring, and it moves north with the warmth like every other spring event. Published carpenter ant windows open in March across the Ohio Valley and the Plains, in April across the Northeast and the Pacific coast, and in May across the Southeast. Florida is the outlier: UF/IFAS puts its carpenter ant flights at dusk and after dark across the rainy season, May through November. Every state page on this site names the agency its window came from.

Antennae, waist, wings. An ant's antennae are elbowed and bend sharply partway along; a termite's are straight and made of small beadlike segments. An ant has a narrowly pinched wasp waist; a termite's abdomen joins its thorax in a straight line. An ant's front wings are longer than its hind wings; a termite's four wings are about equal and roughly twice its body length. University of Maryland Extension adds a fourth: ant forewings are tinted brown, termite wings pale and translucent.

Two different reasons that get confused with each other. Foraging ants come in looking for food and water and for shelter from weather they do not like, which is a nuisance and usually a temporary one. Winged reproductives emerging indoors is a different event: it means a colony has matured inside, underneath, or immediately against the building. The second one is the one worth acting on.

Not one that any agency publishes. We checked roughly twenty land grant extension services and found no numeric air or soil temperature threshold for carpenter ant swarming or for the onset of spring ant activity. UF/IFAS describes flights as triggered by photoperiod and by changes in temperature, which is a direction of travel rather than a value. Numbers that circulate online trace back to pest control marketing sites. This site runs a live soil temperature tool and will not dress it up as a swarm forecast.

Thirteen states plus Puerto Rico, covering 1,015 counties and county equivalents. Six are quarantined in their entirety: Alabama, Florida, Georgia, Louisiana, Mississippi and South Carolina. Seven are quarantined in part: Texas with 189 counties, Tennessee with 87, North Carolina with 77, Arkansas with 50, Oklahoma and Virginia with 23 each, and California with 3. Two recent changes matter. New Mexico came off the list entirely in August 2025. Virginia is on it and expanding, with 10 more localities flagged pending. Figures read from USDA APHIS on August 28, 2026; the quarantine moves, so check APHIS rather than this page before acting.

The odorous house ant is the one most likely to be on your counter across most of the country, and it is also the easiest to confirm: crush one and it smells. Pavement ants dominate sidewalks and slab edges from New England through the Midwest and down the Mid-Atlantic. Carpenter ants are the structural one and the expensive one. Pharaoh ants are the indoor specialist that never leaves and is on no calendar at all.

Different problem, slower clock. Carpenter ants remove wood to nest in it rather than eating it, and they need wood that is already damp or decayed, so an infestation is usually a symptom of a water problem rather than the cause of one. Damage is real but typically takes years to become structural. Termites eat wood, including sound wood, and move faster. Both swarm in spring, which is why so many people find out they have one by mistaking it for the other.

Fire ants bite to hold on and then sting, and the sting burns. Most people get a raised bump that turns into a small fluid filled blister over a day or so. The serious cases are people who are allergic to the venom, where a reaction can be severe and can involve the whole body rather than just the sting site. If a sting reaction worries you, or spreads beyond the sting site, contact a clinician or your state health department.