Termite Season: When Are Termites Most Active?

While termites are active year-round, certain times see heightened activity — particularly swarming. Understanding seasonality helps you time inspections and respond when activity peaks.

When Do Termites Swarm?

Eastern Subterranean

March through May. Warm days (70+ degrees Fahrenheit) following rain. Daytime. Eastern US.

Western Subterranean

September through November. Warm daytime. Pacific Coast.

Formosan

May through June. Warm humid evenings (80+ degrees). Southeastern US, Gulf Coast, Hawaii.

Drywood

August through November. Warm evenings. Southern California, Florida, Gulf Coast, Hawaii.

Dampwood

July through October. Evening. Pacific Northwest, coastal California.

Regional Activity Calendar

Southeast

Highest risk. Year-round activity. Peak swarming February through June. Formosan termites add danger May through June.

Northeast and Midwest

Subterranean swarming March through May. Activity slows in winter but continues below frost line.

Southwest

Desert subterranean termites swarm after monsoon rains. Drywood active year-round in warm areas.

Pacific Northwest

Dampwood swarms in summer. Subterranean swarms in fall.

Year-Round Activity

Swarming is seasonal, but feeding is not. Workers eat year-round and damage accumulates daily. Absence of swarmers does not mean absence of termites.

What to Watch Each Season

Spring: peak subterranean swarming, wings on windowsills, schedule inspections. Summer: Formosan/dampwood peaks, check mud tubes, monitor moisture. Fall: drywood swarming peak, look for frass. Winter: indoor swarms possible, termites remain active.

Timing Treatment

Best time is as soon as termites are detected — regardless of season. Delaying allows damage to accumulate. See prevention tips.

Understanding Why Swarming Happens When It Does

Swarming is not random — it is precisely timed to maximize the chances of successful reproduction. The environmental triggers for swarming have evolved over millions of years to coincide with conditions that give new colonies the best start.

Spring swarms of subterranean termites occur when soil temperatures rise above 70 degrees Fahrenheit and recent rain has softened the ground. The warm, moist conditions make it easier for swarmers to exit the colony through softened soil and provide the humidity that new founding pairs need to survive their first hours in the open.

Formosan termite swarms occur on warm, humid evenings in late spring and early summer. The evening timing coincides with reduced predation from birds and provides the cover of darkness for the weak-flying swarmers. The high humidity of Gulf Coast evenings reduces moisture loss from their soft bodies during flight.

Drywood termite swarms in late summer and fall take advantage of warm evening temperatures while avoiding the competition with subterranean species that swarm in spring. Since drywood termites enter wood directly (rather than nesting in soil), they can take advantage of any warm period to fly and find suitable wood.

What to Do During Termite Season

During peak swarming season in your region, take these proactive steps. Increase your monitoring — check windowsills and door areas daily for discarded wings. Keep exterior lights off in the evening or switch to yellow bug lights that are less attractive to swarmers. Close windows and doors during evening hours or ensure all openings are screened. Walk your foundation perimeter weekly, looking for new mud tubes or other signs of activity.

Schedule your annual professional inspection for early in swarming season. This ensures any new activity is caught quickly and allows treatment before the colony has a full spring and summer growing season to expand.

Regional Swarming Calendars

Here is a more detailed regional breakdown to help you know when to be most vigilant.

Deep South (Florida, Louisiana, Mississippi, southern Texas, southern Alabama, southern Georgia)

This is the highest-pressure region. Subterranean swarms begin as early as January and continue through May. Formosan termites swarm May through June in dramatic evening events. Drywood termites may swarm nearly year-round in southern Florida. Multiple species create overlapping swarming seasons that effectively cover the entire calendar year.

Mid-Atlantic and Upper South (Virginia, North Carolina, Tennessee, Kentucky, Maryland)

Eastern subterranean termites swarm March through May, with peak activity in April. Formosan termites have been found in some areas and swarm May through June. Activity drops significantly in November through February but does not stop entirely in heated structures.

Midwest (Ohio, Indiana, Illinois, Missouri, Iowa)

Subterranean termite swarming occurs March through May, with later starts in northern areas. Winter activity continues below the frost line. Annual inspections should be scheduled in early spring to catch the first signs of the season's activity.

Understanding termite seasonality helps you stay one step ahead of these persistent pests. Mark your calendar for your region's peak swarming season, schedule your annual inspection accordingly, and maintain year-round vigilance. Termites do not take vacations, and your prevention efforts should not either.

Expert Field Observations

After 15 years of tracking termite activity across the Southeast, I have developed a strong sense of seasonal patterns. I schedule my busiest inspection months from March through June, which aligns with peak swarming seasons. But I always remind homeowners that swarming is seasonal while feeding is not -- workers eat your home 365 days a year.

The most common mistake I see is homeowners who associate termite risk only with spring. I have diagnosed active infestations in every month of the year, including January and February. Termite vigilance is a year-round commitment.

-- Sarah Mitchell, BCE, 15 years in Integrated Pest Management

Trusted Sources and Further Reading

• EPA Guide to Safe Pest Control -- EPA resources on seasonal pest management.
• National Pest Management Association -- Regional swarming calendars and seasonal termite activity data.
• University of Florida Entomology Department -- Research on swarming triggers and species-specific timing across climate zones.
• Clemson Cooperative Extension -- Regional guidance on termite seasonality.
• USDA Forest Service -- Data on termite activity patterns across US climate zones.

Main Causes

Subterranean termites reach structures by foraging from soil colonies, building protective mud tubes across foundations and over slab edges to access untreated wood. Drywood termites colonize directly through small flight cuts during seasonal swarms, settling into eaves, attic framing, and exposed structural lumber without any soil contact. Common upstream conditions include wood-to-soil contact at deck posts and porch columns, moisture-damaged framing from roof leaks or plumbing leaks, mulch piled against the foundation, firewood stacked against the house, and untreated wood within six inches of grade. Established outdoor colonies near a structure provide a constant supply of foragers, and a single mature subterranean colony contains 60,000 to several million workers capable of damaging structural wood for years before becoming visually obvious.

How to Identify

Confirm termites through mud tubes, swarmer evidence, frass, hollow-sounding wood, or direct sighting of workers and soldiers in damaged wood. Subterranean termites build pencil-width mud tubes up foundation walls, basement walls, and pier blocks — fresh tubes are moist and dark; old tubes are dry and crumbly. Discarded wings near windowsills or light fixtures after spring rains indicate a recent swarm, often from a colony already inside the structure. Drywood termites leave hexagonal pellet-shaped frass — small, six-sided, sand-grain-sized — kicked out of small holes in infested wood. Tapping suspect wood with a screwdriver handle produces a hollow sound where workers have consumed the interior, even though the exterior surface looks intact.

Risk and Severity

Termites are among the costliest residential pests in the United States, causing several billion dollars in structural damage annually with most damage not covered by standard homeowner insurance. Subterranean termites can compromise sill plates, floor joists, structural beams, and load-bearing framing over months to years, often without external visual evidence. Drywood termites damage attic framing, eaves, exposed beams, and structural lumber in older homes. Damage progresses slowly but cumulatively, and a colony left active for several years can require tens of thousands of dollars in remediation including framing replacement, treatment, and finish repair. Risk scales with how long an infestation has been active, soil moisture conditions, wood-to-soil contact, and gaps in periodic professional inspection.

Solutions and Actions

Termite control should always involve a licensed professional with appropriate state credentials, not DIY treatment, because the products and application protocols are not consumer-grade and incomplete treatment allows continued damage. Subterranean termites are typically eliminated through either a continuous liquid termiticide barrier applied around the foundation or a baiting system using monitoring stations and toxicant-loaded bait around the perimeter. Drywood termites in localized infestations are treated by spot injection of foam, dust, or borate; whole-structure infestations require structural fumigation. Schedule annual professional inspections in active termite regions because early detection dramatically reduces damage and treatment scope. Coordinate any treatment with foundation drainage improvements, wood-to-soil separation, and moisture remediation to prevent reinfestation.

Prevention

Long-term prevention requires moisture control, wood-to-soil separation, and ongoing professional monitoring. Maintain at least a six-inch gap between soil grade and any wood siding, framing, or trim, and use pressure-treated lumber wherever wood approaches soil contact. Pull mulch back at least twelve inches from the foundation, store firewood off the ground and away from the house, and remove old stumps, buried wood debris, and form boards. Address drainage so soil near the foundation does not stay saturated — repair gutters, extend downspouts, and correct negative grade. Inspect for active leaks in roof, plumbing, and HVAC condensate lines annually. Schedule a licensed termite inspection every one to three years depending on regional pressure, and maintain any existing termite warranty or bond.

Frequently Asked Questions

When is termite season?

Swarming season varies by species and region. Eastern subterranean termites swarm March through May, Formosan termites May through June, and drywood termites August through November. However, termites feed year-round.

Are termites active in winter?

Yes. Worker termites continue feeding throughout winter. In heated buildings, colonies near the foundation remain fully active.

Should I schedule my inspection during swarming season?

Early spring (March-April) is ideal because it coincides with peak swarming activity. However, inspections are valuable at any time of year.

Can termites swarm indoors during winter?

Yes. When a colony is beneath a heated building, warmth can trigger out-of-season swarming. Winter indoor swarmers indicate an active colony beneath your structure.