Termite Season: When Termites Swarm and Signs to Watch For

Termite season is the time of year when termite colonies send out winged termites, called swarmers, to start new colonies. In western Washington, that often happens in the fall, right after the first good rains.

That surprises many people, because most national articles say termite season is in the spring. So if you spot winged bugs near a window in Olympia or Lacey this September or October, take a closer look.

At Bigfoot Pest Management, we help South Sound homeowners sort out what they are seeing. Below, we cover when termites swarm here, how to tell them from flying ants, the warning signs to watch for, and what to do next.

What Is Termite Season?

Termite season is the swarming season, not the only time termites are active. Termites feed on wood all year long. They slow down in cold weather, but the colony keeps working underground or inside wood.

Once a colony is big and mature, it produces winged termites. Scientists call them alates or reproductives. On the right day, hundreds of them leave the nest at once. They pair up, drop their wings, and try to start a new colony in moist soil or wood.

Most swarmers die within hours. A swarm, though, is a sign that a mature colony is nearby. If the swarm happens inside your home, the colony may be in or under your house.

When Do Termites Swarm in Thurston County?

In Thurston County, termites swarm mostly in the fall, with some swarms in the spring. Two kinds of termites cause most swarms here.

Western Subterranean Termites

Western subterranean termites (Reticulitermes hesperus) live in the soil and build tunnels up into wood.

According to a Pacific Northwest Extension guide from Oregon State University, they swarm mainly in the fall west of the Cascades and mainly in the spring east of the Cascades.

They swarm in the afternoon, often on a warm, sunny day right after a rain. The swarmers are small and dark brown to black, about 3/8 inch long with their wings.

Pacific Dampwood Termites

Pacific dampwood termites (Zootermopsis angusticollis) live in wet, rotting wood. They fly on warm evenings in late summer and fall, often after rain.

They are much larger than subterranean swarmers, often more than an inch long with wings, and range from cream-colored to dark brown. Like many swarming insects, they may flutter around outdoor lights.

Termite Swarm Timing at a Glance

Termite	Main swarm season in western WA	Time of day	What swarmers look like	Damage risk
Western subterranean	Fall (sometimes spring)	Afternoon, after rain	Small, dark, about 3/8 inch	High over time
Pacific dampwood	Late summer to fall	Warm evenings	Large, over 1 inch, cream to dark brown	Starts in wet wood; can spread as the colony grows

How Long Does Termite Season Last?

A single swarm lasts less than an hour. The swarming season, though, can stretch over several weeks. In Thurston County, the fall season usually follows the first rains of September and October.

Spring swarms may show up on warm days after spring showers.

After swarm season ends, the colony is still there. That is why one quiet month does not mean the problem is gone.

Termite Swarmers vs. Flying Ants

Flying ants and termite swarmers often show up at the same time of year, so they are easy to mix up. Here is how to tell them apart.

Feature	Termite swarmer	Flying ant
Antennae	Straight, like a string of beads	Bent at an elbow
Waist	Thick, no pinch	Thin, pinched waist
Wings	Four wings, all the same size	Front wings longer than back wings
Wings after landing	Break off easily and pile up	Usually stay on

Here in Washington, carpenter ants are the winged ant people most often confuse with termites. Knowing what carpenter ants look like in Washington homes makes the difference easier to spot, since their pinched waist and bent antennae stand out up close.

Their damage looks different too: carpenter ant damage is clean and smooth, while termite damage is packed with soil. A few other bugs that look like flying termites also show up in fall, so a close look is worth the time.

Signs of Termites to Watch For

Swarmers are the most visible sign of termites, but they are not the only one.

Watch for these warning signs in and around your home:

• Swarmers indoors. Winged termites near windows, doors, or lights inside your house are a strong sign of a colony nearby.
• Piles of wings. Termites shed their wings after swarming. Look for small piles of same-sized wings on windowsills and floors.
• Mud tubes. Subterranean termites build pencil-wide tubes of soil and saliva up foundation walls and crawl space piers. These tubes keep them moist and hidden as they travel, which is why termites build mud tubes instead of crawling out in the open.
• Damaged wood. Subterranean termites eat along the grain of the wood and leave soil packed in their tunnels. Dampwood termites leave smooth tunnels with tiny pellets stuck to the walls or scattered on the floor.
• Hollow-sounding wood. Tap on trim, floor joists, or sill plates. Damaged wood may sound hollow or feel soft.
• Blistered paint or sagging floors. These can point to hidden damage under the surface.
• Wet, rotting wood. Soft, damp wood in a crawl space or near a leak is a magnet for dampwood termites.

Early termite wood damage is easy to miss because it often starts inside the wood, behind paint or trim that looks fine from the outside.

Why Thurston County Homes Are at Risk

Termites are less common here than in the South, but they are here. You may read online about drywood termites, which leave piles of dry pellets called frass, or Formosan termites.

Those are mainly southern and California pests. In Thurston County, subterranean and dampwood termites are the ones to watch.

Washington State University included the Olympia area in its termite mapping project. Our wet climate and building styles give termites what they need.

Common risk factors in South Sound homes include:

• Crawl spaces with damp soil, poor airflow, or standing water
• Wood touching soil, like siding, deck posts, or fence boards that meet the ground
• Clogged gutters and downspouts that dump water near the foundation
• Firewood and lumber stacked against the house
• Thick mulch or soil piled up against siding
• Plumbing or roof leaks that keep wood wet

Moisture is the common thread. Wet wood draws dampwood termites, which can move into sound wood as their colony grows. The same moisture problems invite ants and other pests, so fixing a leak or a damp crawl space protects your home in more than one way.

What to Do If You See Termites Swarming

Seeing a swarm is stressful, but you have time to act. Termites do not destroy a house overnight.

Follow these steps:

1. Stay calm and skip the bug spray. Spraying swarmers will not reach the colony.
2. Save a sample. Collect a few swarmers or wings with clear tape or in a sealed plastic bag.
3. Take photos. Note where and when you saw the swarm.
4. Check nearby. Look for mud tubes on the foundation and soft wood near the swarm.
5. Fix water problems. Clean gutters, fix leaks, and move firewood and mulch away from the house.
6. Call for an inspection. A trained technician can confirm the type of termite and find the colony.

Termites and Home Sales in Washington

If you are buying or selling a home, termites may come up during the sale.

Under Washington’s wood-destroying organism (WDO) inspection rules, any WDO inspection done for a sale, exchange, or refinance has to be a complete inspection by a licensed inspector.

Related Questions to Explore

When to Call a Professional

Some termite signs call for a professional right away. Reach out when:

• You see swarmers inside your house.
• You find mud tubes on your foundation or in your crawl space.
• Wood sounds hollow, feels soft, or shows tunnels.
• You see piles of wings on windowsills.
• You have ongoing moisture problems in a crawl space.
• You are buying or selling a home and need answers about wood damage.

Termite colonies are hidden in soil and wood, so DIY sprays rarely reach them. A trained technician knows where to look and what the signs mean. Bigfoot Pest Management is a locally owned, family-run company serving Olympia, Lacey, Tumwater, Yelm, and the South Sound. We are licensed by the Washington State Department of Agriculture (License #84786).

Our team will look for termites, find the moisture and wood-to-soil problems that draw them in, and explain your options clearly. Ongoing pest prevention plans help keep your home protected all year.

Conclusion

Termite season in Thurston County looks different from what you may read online.

• Western subterranean termites swarm mostly in the fall here, often on sunny days after rain.
• Swarmers, discarded wings, mud tubes, and soft wood are the key warning signs.
• Moisture control and a professional inspection are your best defense.

If you have seen winged bugs this fall and want to know what they are, we are here to help. Contact Bigfoot Pest Management to schedule an inspection with your local Olympia pest control team.