TermiteZone

Built from published species range maps and university extension guidance, cited on this page. Last updated July 20, 2026. Who makes TermiteZone

How the swarm-risk score works

A termite swarm is a weather-triggered event: on the right warm, humid day, mature colonies release winged reproductives (alates) to start new colonies. TermiteZone forecasts how likely that is in your area today. No public API does this, so we synthesize it from public data, and we're specific below about what the number is, and what it isn't.

What the number is, and what it isn't

The score is a conditions index, in the same family as a UV index or a pollen forecast. It answers one question: given the termites that live here, how favorable are today's conditions for a swarm flight? It is not a prediction that termites are in your home, and a low score is not an all-clear. Only an in-person inspection can confirm whether a structure is infested.

A fair question: any one colony swarms only about once a year, so how can a daily number mean anything? The answer is synchronization. Colonies of the same species don't swarm on random days, they swarm on the same days, cued by shared weather, so that alates from different colonies meet and predators are overwhelmed.[2] In termite country there are many colonies, so on a "trigger day" you get the mass flights the region is known for, and on the wrong day, nothing. The score tracks that day-to-day, area-level likelihood, not the fate of a single colony.

1. Which termites live here

Each place is mapped to the termite species actually established there, from published university-extension and USDA range maps: native subterranean termites throughout the belt, invasive Formosan termites across the Gulf South and warm coasts,[3] drywood termites in coastal California, Arizona, and the southern tier,[5] and desert subterranean termites in the low deserts of the Southwest.[4]

2. When each one swarms

Every species has its own swarm season, encoded from the entomology literature and shifted by latitude: spring daytime flights for native subterraneans (earlier in the Deep South), warm-humid dusk flights in late spring and early summer for Formosan, late-summer and fall flights for drywood, and monsoon-season night flights for desert subterraneans. These windows come from documented flight phenology, where each species maintains its own seasonal timing.[1]

3. What the weather is doing

For each day we pull live temperature, humidity, dew point, and recent rainfall from Open-Meteo and score how well they match each species' documented swarm cues: enough warmth (cool temperatures are the main thing that shuts flights down),[1] mugginess, and a recent-rain boost.[3] Season tells us whether a flight is possible; the weather tells us whether today is actually a flight day.

Putting it together

Each species contributes season × weather-trigger × local establishment × a relative swarm intensity, and we sum the contributions and scale to a 0 to 100 index. A place with two species in overlapping season (native and Formosan on the Gulf) can reach the top of the scale, which is correct: that is peak regional swarm pressure.

Honest limits

  • The inputs (species ranges, swarm seasons, and the weather cues) are drawn from the sources below. The exact index math, the curve shapes and the calibration, is our own synthesis and has not been fitted to observed swarm counts. Read the digits coarsely: green, amber, or red matters more than 68 vs. 72.
  • A low score does not mean termites are absent, only that a flight is unlikely today.
  • Coverage is the Termite Belt (TIP Regions I–II); we do not score the far northern U.S.
  • Only a professional inspection can confirm an active infestation.

References

The biology the model rests on. The index math is ours; the science below is not.

  1. [1] Chouvenc T, Scheffrahn RH, Mullins AJ, Su N-Y (2017). Flight phenology of two Coptotermes species (Isoptera: Rhinotermitidae) in southeastern Florida. Journal of Economic Entomology 110(4):1693–1704.Low temperature is the primary factor gating termite dispersal flights, each species has its own seasonal window, and once alates mature, flights proceed promptly when conditions turn favorable.
  2. [2] Mizumoto N, Nozaki T (2024). The significance of social interactions in synchronized swarming flight in a termite. Biology Letters 20(11):20240423.Alates release their dispersal flight in a synchronized way, modulated by temperature and social cues, which is why colonies across an area tend to swarm on the same days.
  3. [3] LSU AgCenter. Formosan Subterranean Termites.Formosan flights peak in May in Louisiana on warm (~80°F), humid, low-wind evenings after heavy rain, at dusk toward lights.
  4. [4] University of Florida IFAS. Featured Creatures: termites.Species identification, range, and swarm timing for the subterranean, Formosan, and drywood termites.
  5. [5] UC IPM. Drywood Termites; Western Drywood Termite.Drywood termite range in the West and Southwest and its warm-season, soil-independent flights.
  6. [6] International Code Council. Termite Infestation Probability Map, IRC Figure R301.2(7).The building-code map of U.S. termite pressure (Regions I–IV) that defines TermiteZone's coverage area.

See the termite species guide for each termite's range, swarm timing, and signs.