When Does Termite Season Start? A Region-by-Region U.S. Timeline

Most people meet termites the same way: a warm afternoon, a window left in the sun, and suddenly a few dozen winged insects crawling up the glass. That moment has a name — a swarm — and it is the reason “termite season” exists as a phrase at all. The colony itself never takes a season off. Workers eat wood twelve months a year, in January as happily as in June. What changes with the calendar is the one day the colony becomes visible.

A swarm is a mature colony sending out winged reproducers — swarmers, or alates — to start new colonies. And that is the part worth sitting with: a colony does not produce swarmers until it is roughly three to five years old. If swarmers are coming out of your wall, the colony behind them is not new. It has been there, eating, for years.

So the useful question is not “is it termite season?” but “when do termites swarm where I live?” — because that is the window when an established colony finally announces itself. Here is the honest, region-by-region answer.

The U.S. termite timeline, region by region

Gulf Coast and the Deep South — late February to June

The season opens earliest here. In coastal Louisiana, Mississippi, Alabama and Florida, native subterranean termites can swarm by late February, and the peak arrives through March. Then comes the second act that this region alone gets at full strength: Formosan termites, which swarm on humid evenings from April into June, in huge numbers, around porch lights and street lamps. A daytime swarm here usually means native subterraneans; a swarm at dusk in May points at Formosans — and Formosan colonies run many times larger, which is why coastal cities such as Charleston treat them as a different problem, not just more of the same one.

The Southeast and Mid-Atlantic — March to May

Georgia, the Carolinas, Tennessee, Virginia and Maryland follow a few weeks behind the coast. Eastern subterranean termites swarm mostly in March and April, typically on the first genuinely warm day after a rain. The pattern moves with soil temperature, which is why Memphis regularly sees swarms two or three weeks before Nashville does in the same state.

Texas and the South-Central states — March to May, then a late-summer echo

Subterranean swarms run March through May across Texas, Oklahoma and Arkansas. Along the Texas coast there is a second, quieter event: drywood termites swarming in late summer and early fall. Drywoods do not need soil contact, so their swarmers can start a colony in a fascia board or an attic — a different threat with a different treatment.

The Midwest and Plains — April and May

From Missouri and Kansas up through Ohio, Illinois, Iowa and Nebraska, soil warms later, so swarms concentrate in April and May. The season is shorter and sharper than in the South — often a single week when every mature colony in a neighborhood flies within days of each other.

The desert Southwest — July to September, with the monsoon

Arizona, New Mexico and the desert edge of Southern California break the spring rule entirely. Desert subterranean termites wait for the summer monsoon, swarming from July into September after heavy rain. If you are in Phoenix and see swarmers in August, that is not late — that is exactly on schedule.

California’s coast — a fall and winter season

Coastal California runs on its own calendar too: drywood termites swarm on warm, still days in September and October, and the native subterraneans often fly with the first soaking winter rains. Californians are the one group who should take a November swarm completely seriously.

The Pacific Northwest — August and September, mostly dampwood

Western Washington and Oregon see dampwood termite swarms in late summer — but dampwoods only infest wood that is already wet, so they are usually a symptom of a moisture problem rather than the main event. In this region the structural insect that actually deserves the worry is the carpenter ant, which is its own story.

Is it a termite — or a flying ant?

Swarming ants fly in the same seasons, and most “termite” photos sent to pest companies are ants. Three checks settle it:

• Waist: ants have a pinched waist; termite swarmers are straight-sided, almost tube-shaped.
• Wings: ants have longer front wings than back wings; termite wings are all the same length — and they shed easily. A windowsill full of identical silvery wings, with no insects, is a termite calling card.
• Antennae: ants’ are bent at an elbow; termites’ are straight, like tiny strings of beads.

You saw a swarm. Now what?

First, what not to do: do not spray the swarmers and consider it handled. Swarmers cannot bite, cannot chew wood, and die on their own within a day. Killing them changes nothing about the colony that produced them — it is like fixing a fire by unplugging the smoke alarm.

Do this instead. Note the date and take a photo, even a bad one — species identification from a swarmer photo is how a professional knows whether you are dealing with natives, Formosans or drywoods, and the date tells them how confident to be. Check window sills and spider webs for shed wings, and walk the foundation looking for pencil-width mud tubes. Then get an inspection on the calendar. Swarms inside the house, wings on interior sills, or mud tubes on the foundation are the three signs that move this from “keep an eye on it” to “have someone out this month.”

If that is where you are, our termite control page explains what a proper inspection and treatment involves and what it typically costs, and the coverage directory will tell you whether we can connect you with a licensed local pro in your city.

Quick answers

Does a swarm mean my house is infested? Not necessarily — swarmers fly from a colony that may be in a stump or a neighbor’s yard. But a swarm inside your home almost always means the colony is in or under the structure.

How long does swarm season last? The regional window runs weeks, but each individual colony flies for only a day or two. Miss it, and the next visible sign may be a year away — or it may be damage.

Is there any month with zero termite risk? No. Swarming is seasonal; eating is not. A February inspection in Minnesota can still find an active colony working a warm crawl space.