The Washington State Climate Office’s summer 2026 outlook puts western Washington on track for warmer and drier than normal conditions from July through September. For Olympia homeowners, that forecast isn’t just weather trivia. It’s the reason stinging insect activity feels noticeably more intense this year than it did in wetter summers past. More overwintering queens survive mild winters, colonies get an earlier start in spring, and by the time August arrives, nests that seemed minor in June have grown into a genuine problem.

At Olympia Pest Management, we work across Thurston, Mason, Lewis, Grays Harbor, and Pierce counties through every season, and the pattern we see each summer is consistent: calls spike in late August, right before Labor Day, when homeowners discover that the wasp traffic they’d been watching for weeks has grown into something they can’t manage on their own. What follows is what we know about what’s happening on Olympia properties this summer and how to stay ahead of it.

Why Wasp Activity Feels Stronger This Summer

Warmer, drier conditions favor stinging insects in three concrete ways. More overwintering queens survive to spring, which means more colonies get started. Those colonies reach productive size earlier in the season. And as natural food sources like nectar and ripe fruit dry up or become scarce, yellow jackets shift to scavenging, which brings them closer to homes, garbage cans, and outdoor dining areas.

In Olympia, a colony that was a few dozen workers in June can reach several thousand by mid-August. That’s not an exaggeration; it’s the normal trajectory of a yellow jacket colony in a favorable season. The nest you noticed but decided to watch often isn’t the same-sized nest you’re dealing with six weeks later.

Which Wasps You’re Most Likely to Encounter

Not every stinging insect you see this summer is the same species, and the differences matter when deciding how to respond. Here are the four most common in and around Olympia.

Western Yellow Jacket (Vespula pensylvanica)
This is the yellow jacket most people picture: yellow and black banding, aggressive when disturbed, and prone to nesting underground or inside wall voids. It’s the dominant stinging pest in western Washington and the species most likely behind the traffic you’re seeing near your lawn or garden beds.

German Yellow Jacket (Vespula germanica)
The German yellow jacket favors structural voids: wall cavities, attics, and crawl spaces. That distinction matters for Olympia properties, where damp crawl spaces are common and often go unchecked for long stretches. A colony inside a wall void can reach thousands of workers before a homeowner notices anything beyond a few wasps entering a gap in the siding.

European Paper Wasp (Polistes dominula)
This introduced species is now more common in Olympia-area suburbs than native paper wasp species, which tend to stay in more rural or forested areas of Lewis and Mason counties. The European paper wasp builds the classic open-cell umbrella-shaped nest you’ll find under eaves, inside window frames, or in sheltered gaps. Colonies top out around 20 to 75 workers and are far less aggressive than yellow jackets when they aren’t directly threatened.

Bald-Faced Hornet
Despite the name, the bald-faced hornet is technically a yellow jacket species with distinctive black-and-white coloring. It builds large gray paper nests in trees, shrubs, and on building exteriors. A mature nest by mid-summer can hold up to 700 workers, and the colony is highly defensive of its territory. If you’re seeing a large wasp you don’t recognize, it’s almost certainly this species. Northern giant hornets were eradicated from Washington state; the last known nest was destroyed in 2021, and the USDA and Washington State Department of Agriculture declared the species eradicated from the US in December 2024.

Where Nests Are Hiding on Your Property

The location of a nest determines how dangerous it is and what kind of response it requires. Most underground yellow jacket nests aren’t dug fresh from scratch. They’re built inside abandoned rodent burrows or existing soil cavities. That means properties with prior rodent activity face higher yellow jacket nesting risk the following season. Wooded lots throughout Thurston County create exactly these conditions: more soil disturbance, more existing burrows, and more sheltered ground-level sites.

German yellow jackets complicate things further because their preferred nesting sites are inside structures rather than in the ground. A crawl space with a deteriorating vent screen or a gap behind exterior trim is an ideal entry point. By the time the colony is audible inside a wall or workers are emerging in an interior room, the nest is well established and removal requires more than a can of spray.

Watching flight patterns is often the most reliable way to find a hidden colony. Wasps follow consistent paths between the nest and food sources. Repeated traffic entering a single point (a gap in siding, a crawl space vent, a ground-level opening in a retaining wall) is a reliable indicator of what’s behind it.

When to Act & When to Leave It Alone

Not every wasp nest requires immediate treatment. A small European paper wasp nest with a handful of workers under an eave in a low-traffic corner of the property is often not worth disturbing. They provide some benefit as predators of garden pests, and a colony that size poses little risk if left alone.

The calculation changes in several situations.

Underground yellow jacket nests warrant professional attention regardless of apparent size, because the full colony is underground and larger than anything visible at the surface.
Any nest inside a wall void, crawl space, or attic needs professional handling; spraying an entry point without treating the colony pushes workers to find a new exit, sometimes into living spaces.
Nests near walkways, doorways, or play areas shouldn’t be left until they’re a problem, because by the time they become one, the colony is at maximum size.
Any household member with a known sting allergy makes even a small, accessible nest a situation for professionals. Serious allergic reactions to insect venom, including anaphylaxis, affect a meaningful portion of the population, and a colony near a regularly used outdoor space isn’t a reasonable risk to take.

Late August through mid-September is the highest-risk window in Thurston County. Colonies are at peak population, workers shift from feeding larvae to scavenging carbohydrates, and late-summer outdoor gatherings bring people into close contact with mature nests. This is when alarm pheromones (the chemical signal that triggers mass defensive responses) become a genuine concern. One disturbed wasp can recruit dozens of others within seconds.

Practical Steps to Reduce Encounters Around Your Property

Some of the most effective prevention steps don’t involve any products at all.

Secure garbage and recycling. Yellow jackets treat unsecured food waste as a reliable food source. Keep outdoor bins covered and rinse sweet residue from recycling containers before setting them out.
Use traps selectively. Wasp traps using synthetic attractants like n-heptyl butyrate can reduce worker traffic near an outdoor dining area, but they don’t control an active colony or prevent new nests from forming. Think of them as temporary relief, not a solution.
Seal structural entry points in fall. After colonies die off in late fall, gaps in eaves, crawl space vents, and roofline openings become overwintering sites for new queens. Sealing those points before the following spring eliminates some of the most common nesting sites on Olympia properties and reduces the likelihood of a colony establishing in the same void the next season.
Address prior rodent activity. If your property had rodent pressure in previous seasons, treat any visible burrows in the lawn or garden beds. Abandoned rodent tunnels are among the most common starting points for underground yellow jacket nests.

What an Integrated Approach Actually Looks Like

Integrated pest management (IPM) applies here in a practical way. For stinging insects, it means starting with inspection to confirm the species and locate the nest before deciding on any treatment. A nest inside a crawl space requires a different approach than an aerial paper wasp nest under an eave. Species identification, nest location, proximity to activity areas, and the presence of allergy risk in the household all factor into a reasonable plan.

Treating the nest itself is only part of it. Sealing the entry point, addressing conditions that made the site attractive in the first place, and scheduling a follow-up to confirm the colony has been addressed are the steps that work to prevent the same problem from appearing next season. One-time reactive treatment without that follow-through tends to produce the same call the following summer.

Late summer is exactly when a wasp situation that seemed manageable starts moving fast. If you’re not sure what you’re dealing with, or if you already know and don’t want to handle it yourself, we offer free initial inspections and same-day availability across Olympia and Thurston County. Contact us at (360) 819-1230.