Today's Mosquito Risk in Ohio: Real-Time Forecast & Activity Map
Check your ZIP code for local mosquito activity, West Nile risk, and prevention insights.
Built from CDC and NOAA data
Mosquito Surveillance Insights
- Annual WNV Cases
- about 50 to 100 confirmed cases annually
- Based on CDC ArboNET surveillance data
- Risk Tier
- Tier 3: Moderate
- Lake Erie heat island plus Ohio River humidity push Cx. pipiens populations through August peaks.
- Per mosquito-risk-model regional tier
- Highest-Risk Areas
- Cuyahoga, Franklin, Hamilton, Lucas (WNV)
Current Situation in Ohio
Ohio carries a moderate WNV burden of roughly 50 to 100 confirmed human cases in a typical year, with risk concentrated in the Cleveland, Columbus, and Cincinnati metros. Cx. pipiens populations breeding in city storm drains and rowhouse alley catch basins drive most transmission, sustained by August heat off Lake Erie and Ohio River humidity. Aedes albopictus is established across the southern half of the state and pushing north each year, dominant in suburban Cincinnati and Dayton daytime biting. EEE is rare. The Lake Erie shoreline marshes, the Maumee River bottomlands, and inland glacial wetlands like Killbuck Marsh and Mentor Marsh produce steady seasonal Aedes vexans hatches. Wayne National Forest in the southeast holds woodland Aedes off beaver ponds. Biting season runs June through September.
Snapshot of the current mosquito situation in Ohio, drawn from CDC ArboNET surveillance and the regional risk model.
- Risk Level
- Moderate
- Peak Activity
- June through September
- Dominant Vector
- Northern House Mosquito (Culex pipiens)
Where Mosquitoes Breed in Ohio
Ohio mosquito habitat splits between the Lake Erie shoreline, the Ohio River corridor, and the inland glacial wetland mosaic. The Lake Erie marshes from Toledo through Sandusky and Mentor produce sustained Aedes vexans and Cx. pipiens populations through summer, with Mentor Marsh and the Maumee Bay wetlands as the biggest single producers in the north. The Ohio River bottomlands at Cincinnati, Portsmouth, and Marietta sustain steady Cx. pipiens and Aedes albopictus populations. Inland, Killbuck Marsh in Holmes and Wayne counties and the Mosquito Creek wetlands of Trumbull County produce dense glacial-pothole hatches. Wayne National Forest hollows hold woodland Aedes off forested wetlands. Storm drains and tire piles across Cleveland, Columbus, Cincinnati, Toledo, and Akron carry the urban Cx. pipiens and Aedes albopictus load.
Hotspot Counties & Areas
- Cuyahoga County (Cleveland metro, Lake Erie shoreline)
- Franklin County (Columbus metro)
- Hamilton County (Cincinnati, Ohio River)
- Lucas County (Toledo, Maumee Bay marshes)
- Summit County (Akron, Cuyahoga River corridor)
- Trumbull County (Mosquito Creek wetlands)
- Killbuck Marsh (Holmes and Wayne counties)
- Wayne National Forest hollows
Seasonal Activity Pattern
Biting starts in early June, peaks late July through August, and tapers through September. WNV cases concentrate in August across the Cleveland, Columbus, and Cincinnati metros. The Ohio River corridor runs warmer and longer than the Lake Erie shoreline, with Cincinnati biting tailing into early October. Aedes albopictus daytime biting in suburban yards across the southern half of the state runs heavy from July through September. Heavy summer storms produce floodwater Aedes pulses along the Maumee, Cuyahoga, and Ohio River bottomlands. Wayne National Forest hollows run a week or two behind the metros on phenology.
Monthly Biting Intensity (Midwest)
Ohio Mosquito Risk Profile
- WNV burden level
- Moderate
- about 50 to 100 confirmed cases annually
- EEE risk
- Rare
- Peak biting season
- late May through September
- Top urban risk areas
- Columbus (Franklin)
- Cleveland (Cuyahoga)
- Cincinnati (Hamilton)
- Toledo (Lucas)
Signature habitat: Lake Erie shoreline, Ohio River corridor, urban Cleveland and Columbus storm drains, glacial wetlands.
Climate driver: Lake Erie heat island plus Ohio River humidity push Cx. pipiens populations through August peaks.
Check Your Local Mosquito Risk
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Common Mosquitoes in Ohio
Understanding which mosquitoes are active in Ohio helps you identify threats and take appropriate precautions. Click any card for details.
Northern House Mosquito
Culex pipiens
Risk: West Nile virus, St. Louis encephalitis, dog heartworm.
Key feature: Medium brown body with banded abdomen. Looks nearly identical to Cx. quinquefasciatus.
Active: Late spring through early fall in the north. Adult females overwinter in basements, garages, and storm drains.
Inland Floodwater Mosquito
Aedes vexans
Risk: Aggressive nuisance biter. Weak vector for West Nile, dog heartworm.
Key feature: Brown body with pale bands on the legs and a tapered abdomen.
Active: Spring through fall. Population spikes a week or two after major rain events.
West Nile Virus
Vector: Northern House Mosquito
West Nile Virus
The dominant West Nile vector across the northern half of the US. About 80% of infections are asymptomatic.
What to watch for
- Onset typically 2 to 15 days after a bite
- Most cases mild or asymptomatic, small fraction severe
- Neurological signs (severe headache, neck stiffness, confusion) need ER care
Breaking the Cycle in Ohio
The mosquito lifecycle takes about a week. These habits cut local biting pressure faster than anything else, building multiple layers of protection.
Drain the Yard Weekly
Empty buckets, planter saucers, kiddie pools, tarps, and clogged gutters. A week of standing water is one full mosquito generation.
Repel Before Going Out
EPA-registered DEET (20-30%), picaridin (20%), IR3535, or oil of lemon eucalyptus. Apply before going outside, especially at dusk and dawn.
Seal the House
Window and door screens with no tears. AC and porch fans both work. Mosquitoes struggle to fly upwind even at 1-2 mph air speed.
Treat Outdoor Clothing
Permethrin-treated long sleeves and pants for evening yard work, hiking, or fishing. Remains effective through 70+ wash cycles.
If You Develop Symptoms
Most mosquito bites are harmless. A small fraction can transmit illness, and knowing the timeline matters more than panicking at every itch.Five things to know.
Watch for fever
Fever, body aches, headache, or fatigue 2 to 15 days after a bite. West Nile often feels like flu, and most infections never get diagnosed.
Note where and when
A rough record of where and when you got bitten helps your doctor decide what to test for. Date, location, mosquito-heavy areas you visited.
Get help fast for neuro signs
Severe headache, neck stiffness, confusion, vision changes, or sudden muscle weakness can mean neuroinvasive WNV or EEE. Both are medical emergencies.
Pregnant exposure?
If pregnant and bitten in an area with documented Zika or local dengue transmission, mention to your OB. Same goes for travel exposure.
Children and seniors
Higher risk of severe disease from WNV, EEE, and dengue in adults over 60 and children under 5. Early call to the pediatrician or PCP if symptoms appear.
Heading to a lake in Ohio?
Live water temperatures and swim conditions for Lake Erie.
See Ohio lake temperaturesWhen does mosquito season end in Ohio?
Mosquito activity winds down after the first hard freeze, which in Ohio typically arrives around Oct 16. See the local first-frost window and city-by-city freeze dates.
Ohio first frost datesAlso worried about ticks in Ohio?
Lyme disease risk and tick activity track different seasonal patterns than mosquitoes. See your Ohio tick forecast.
View Ohio tick forecastStay Safe in Ohio
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