The short version
Around Olympia, mosquito season runs from late May until the first frost. Treatment means removing water and treating what you can't drain. A barrier spray follows every few weeks.
- Dump standing water every week.
- Evening biters are usually house mosquitoes.
- Barrier sprays last about three to four weeks.
- Larvicide handles water you can’t drain.
- Use repellent with DEET, picaridin or IR3535.
Homeowners and renters in Olympia who want their yard back.
What to look for
In summer heat, eggs become biting adults in about a week. Mosquitoes breed in standing water, even a bottle cap's worth. Often the source is a neighbor's yard or a storm drain.
- 1Kiddie pools left full for days.
- 2Welts on ankles and calves after yardwork.
- 3Ornamental pond with no fish or pump.
- 4Clogged gutters holding water after rain.
- 5Corrugated downspout extensions that never drain.
- 6Standing water in low spots a week after rain.
Why it’s worth acting soon
- Each new generation is bigger than the last.
- Bites can spread West Nile virus.
- Itchy welts, especially for kids.
- Heartworm risk for dogs.
bite, to get protein for their eggsOnly female mosquitoesUS CDC in standing water, from a bottle cap to a pondMosquitoes breedUS EPA West Nile virus is the most common mosquito-borne disease in the U.S.Mosquito diseasesUS CDC 📅
Mosquito activity through the year in Olympia
Spring
clean gutters and dump water as snow melts.
Summer
short but busy in Olympia. Watch for swarms after rain.
Fall
the first frost ends the season.
Winter
store containers upside down and plan for spring.
Treatment options and typical costs
Property Inspection for Breeding Sites
$0–$150 (often bundled with a first treatment)
An inspection in Olympia also gives you a realistic idea of how much a treatment can do on your lot. A wetland yard is a different job from a dry cul-de-sac.
- Time
- 30–60 minutes
- Best for
- Every yard; finds where mosquitoes actually breed
Source Reduction and Larviciding
$75–$150 per visit
Because larvicide works on mosquitoes that can't fly away yet, it's the foundation of most plans in Olympia. Adult spraying is the follow-up, not the fix.
- Time
- 45–90 minutes
- Best for
- Yards with standing water, clogged gutters, ponds, or drains
Monitoring and Seasonal Plans
$50–$150 per follow-up visit; $350–$900 per season bundled
Seasonal plans in Olympia usually bundle barrier spray every 3–4 weeks with larvicide checks and a fall wrap-up visit. Paying per season often beats paying per visit.
- Time
- 15–30 minutes per check; season runs spring through first frost
- Best for
- Anyone who wants the yard usable all summer
Barrier (Residual) Yard Treatment
$75–$200 per visit; $350–$900 per season
A barrier treatment coats the undersides of leaves, shrubs, and shaded surfaces where adult mosquitoes rest during the day around your Olympia home. Adults that land there pick up a lethal dose.
- Time
- 20–45 minutes per visit, repeated every 3–4 weeks
- Best for
- Shaded yards with shrubs, ivy, and dense landscaping
Prices are typical published ranges. Ask what’s included before you compare quotes.
A treatment visit covers the shaded plants and beds where adults rest, along with any standing water that can't be drained.How mosquito treatment works in Olympia.
Barrier spray covers shady shrubs and leaves. Larvicide handles water you can't drain, like ponds or drains. Around Olympia, the season runs from late May until the first frost, so a plan usually starts in spring and runs to the end of the season. Then spray where the adults rest. First, find and remove the water where they breed. Treatment has two parts.
Which mosquitoes bite around Olympia.
They can travel a long way from where they hatch. Floodwater mosquitoes hatch in big waves after heavy rain or snowmelt. They're the main West Nile carriers. They breed in storm drains. House mosquitoes (Culex) bite from dusk into the night.
Mosquitoes that bite indoors usually slip in through gaps around doors or torn window screens.Mosquito season in Olympia.
The season is short, but numbers can spike after rain. West Nile cases usually peak in late summer.
A year of mosquitoes in Olympia.
- Spring: clean gutters and dump water as snow melts. - Winter: store containers upside down and plan for spring. - Fall: the first frost ends the season. - Summer: short but busy in Olympia. Watch for swarms after rain.
The weekly water walk.
- Saucers and pots: empty them or add sand. - Gutters: clear leaves so water drains. - Tree holes: fill them with sand. - AC drip lines and downspouts: make sure water drains away. - Pet bowls: refresh daily. - Birdbaths: change the water twice a week. - Tarps and covers: pull them tight so water runs off. - Toys and buckets: store them upside down.
Avoiding bites.
- Clothing: long sleeves and pants help at dusk. - Repellent: DEET, picaridin, IR3535 or oil of lemon eucalyptus. - Timing: tiger mosquitoes bite by day; house mosquitoes at dusk. - Screens: repair holes in window and door screens. - Fans: a patio fan keeps weak-flying mosquitoes away.
Low-cost ways to cut mosquitoes.
- Mosquito fish: they eat larvae in ornamental ponds. - Mosquito dunks: Bti tablets kill larvae in rain barrels and ponds. - Lights: yellow bug lights attract fewer insects to the porch. - Trimming: thin out dense shrubs and tall grass. - Pumps and fountains: moving water breeds far fewer mosquitoes.
Mosquito or look-alike?
- Non-biting midges: swarm near water at dusk. Harmless, just annoying. - Crane flies: look like giant mosquitoes. They don’t bite. - Mosquitoes: slim, long legs, and a needle-like mouth. - No-see-ums: tiny biting gnats near marshes. Screens need a finer mesh.
When a bite needs a doctor.
Spreading swelling or an infected-looking bite needs a check too. See a doctor for high fever, stiff neck or confusion. About one in five get a fever, headache or body aches. Most people infected with West Nile virus never feel sick. Most bites just itch for a few days.
Protecting your pets.
Talk to your vet about year-round prevention. Heartworm reaches dogs through mosquito bites, and cats can get it as well; Olympia's June–October season is long enough that most vets advise year-round prevention. Refresh pet water bowls daily; with about 51 inches of rain a year in Olympia, bowls and plant saucers refill themselves. Keep animals inside until a yard treatment dries.
What a treatment visit looks like.
They dump or treat standing water. The tech walks the yard first. A visit usually takes 20 to 45 minutes. Most plans repeat every three to four weeks. Then they spray shady shrubs, where adults rest. Larvicide goes in water you can't drain.
Rain barrels and ponds.
- Ponds: fish and moving water keep larvae down. - Barrels: cover openings with fine mesh. - Pool covers: drain standing water after rain. - Tarps: shake out any that hold rainwater. - Gutters: clear them so water drains away. - Bird baths: change the water every few days.
Questions to ask before you sign.
- How often will you come? - What product will you spray? - When can kids and pets go back outside? - How do you protect bees and flowers? - What happens if bites come back between visits? - Do you treat standing water too?
What affects the price
- Travel distance from the company's base.
- Standing water requiring larvicide.
- One-time visit versus a seasonal plan.
- Amount of shade and dense vegetation.
- Commercial or multi-unit property.
- Gutter cleaning or drainage fixes bundled in.
📊
What's your biggest concern about mosquitoes?
When to call for help
early in the season, before the first big wave. Ponds, drains and dense shrubs are hard to handle yourself. Call if bites still keep you indoors. Dumping water should come first.
What you can do yourself
They also spray where adults rest, every few weeks. A pro adds larvicide for water you can't drain. Use repellent and run a fan on the patio. The biggest win is free: dump standing water every week.
Mosquitoes in Olympia
Around Olympia, take a minute to note where you have seen activity and when it appears, so the inspection is faster and the quote more accurate. A local provider who knows Olympia and Washington can point out the specific conditions that matter most here before you commit to a plan. Around Olympia, before you book, ask whether the inspection is included, what the treatment plan covers, how many visits to expect, and what the written quote includes. Around Olympia, getting the scope, the prep steps, and any follow-up terms in writing makes it much easier to compare providers fairly, and a good provider will walk you through each of these without pressure. Around Olympia, a little preparation usually makes the visit more useful: clear access to the areas where you have seen activity, put away loose items, and note anything you have noticed recently. Around Olympia, if you have photos or a rough timeline of when the problem started, share them, because those details help the provider confirm what is going on and give you a more accurate scope and price. Olympia gets about 51 inches of rain a year, so containers and low spots refill constantly through the season. Summer highs around 78°F in Olympia speed up the life cycle, and average humidity near 77% keeps adults active. In Olympia's neighborhoods, the usual sources are gutters, plant saucers, kids' toys and birdbaths. Olympia has a marine west coast climate, and mosquitoes activity here tends to pick up late spring through early fall; year-round in the deep south. Around Olympia, most of the housing is suburban, so the usual entry points, moisture spots, and sheltered areas near the structure are what an inspection checks first.
Local research
Mosquitoes in Olympia, WA: what the public record shows
Before you compare quotes, it helps to know which mosquitoes actually live in Washington, when they are busiest around Olympia, and what the state figures look like. Everything below links to the agency or university page it came from.
West Nile neuroinvasive disease cases, 2024
Neuroinvasive counts are the most reliable state comparison because nearly all severe cases are diagnosed and reported.
CDCWhen mosquitoes are busiest around Olympia
Washington DOH: detections from May (earliest) to October (latest). California reports its heaviest WNV activity in late summer; CDC peak is late August to early September.
Rules that apply in Washington
For context, nationally
- 1,808 — West Nile virus disease cases reported, 2024. CDC
- 1,347 (75% of cases); 173 deaths — West Nile neuroinvasive disease cases, 2024. CDC
Sources: CDC; Washington State Department of Health. Figures are quoted as the source prints them. How we check our sources
Simple ways to keep mosquitoes away
- Keep pools chlorinated and covered when unused.
- Talk with neighbors about shared breeding sites.
- Screen or lid every rain barrel.
- Wear DEET or picaridin repellent outdoors.
- Rake leaf litter from shaded beds.
- Drop Bti dunks in water you cannot drain.
Jot down where you found standing water and when you get bitten. It gives a pro a head start.Did you know?
Over 3,500 mosquito species exist worldwide
A female's wings beat hundreds of times per second
Questions people ask
Are misting systems worth it?
They're costly to install and need refills. Most yards do fine with source removal and regular spraying. For a few homes, yes.
Do I need a seasonal plan or is one treatment enough?
Barrier sprays fade in three to four weeks. Steady relief takes repeat visits. One treatment helps for an event or a few weeks.
Will mosquito treatment kill bees and butterflies?
Ask them to skip blooming plants. Spraying when bees rest helps too. It can if spray hits flowers.
What should I do before the pro arrives?
Move toys and pet bowls. Tell them where you get bitten most. Dump standing water.
Why are there so many mosquitoes in my yard specifically?
Usually there's water nearby, like a clogged gutter or tarp. Shady, damp plants give them a place to rest.
When is mosquito season in Olympia?
It runs from late May until the first frost.
Do mosquitoes in Olympia carry West Nile?
Cases usually peak in late summer. Repellent and dumping standing water are your best protection. They can. West Nile is found in every lower-48 state, Washington included.
Nearby cities
Related guides
Sources (10)
The facts in this article come from the public sources listed above. Every home is different, so ask the company you talk to about pricing and what’s included. Published by Mosquito Exterminator · Updated September 11, 2026 · How we write these guides