Today's Mosquito Risk in Indiana: 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 30 to 60 confirmed cases annually
- Based on CDC ArboNET surveillance data
- Risk Tier
- Tier 3: Moderate
- Southern Indiana borders Aedes albopictus range; northern Indiana stays Culex-dominated.
- Per mosquito-risk-model regional tier
- Highest-Risk Areas
- Marion, Allen, Vanderburgh, St. Joseph (WNV)
Current Situation in Indiana
Indiana carries a moderate WNV burden of roughly 30 to 60 confirmed human cases annually, with risk distributed across the Indianapolis, Fort Wayne, Evansville, and South Bend metros. Cx. pipiens dominates Culex transmission statewide. Aedes albopictus is established across the southern half of the state, with Evansville and the Ohio River corner carrying the densest populations. EEE is rare. The Wabash River bottomlands cutting diagonally across the state and the Ohio River floodplain along the southern border produce heavy Aedes vexans hatches after summer storms. The Indiana Dunes and Lake Michigan shoreline in the northwest hold seasonal coastal Aedes populations. Hoosier National Forest hollows in the south and the Patoka River bottoms produce woodland Aedes off beaver ponds. Biting season runs June through September.
Snapshot of the current mosquito situation in Indiana, 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 Indiana
Indiana mosquito habitat is built on the Wabash and Ohio River bottomlands, the glacial wetland mosaic of the central till plain, and the Lake Michigan shoreline. The Wabash River corridor from Lafayette through Terre Haute and Vincennes produces sustained Aedes vexans and Cx. pipiens populations through summer. The Ohio River floodplain at Evansville and the Patoka River bottoms hold the densest Aedes albopictus in the state. Hoosier National Forest hollows produce woodland Aedes off forested wetlands and beaver ponds. The Indiana Dunes and Lake Michigan shoreline in Lake and Porter counties sustain coastal Aedes vexans hatches. Storm drains and tire piles across Indianapolis, Fort Wayne, Evansville, South Bend, and Gary carry the urban Cx. pipiens and Aedes albopictus load.
Hotspot Counties & Areas
- Marion County (Indianapolis metro)
- Allen County (Fort Wayne, Maumee headwaters)
- Vanderburgh County (Evansville, Ohio River)
- St. Joseph County (South Bend)
- Lake County (Gary, Indiana Dunes)
- Tippecanoe County (Lafayette, Wabash River)
- Hoosier National Forest hollows
- Patoka River bottoms
Seasonal Activity Pattern
Biting starts in early to mid June, peaks late July through August, and tapers through September. WNV cases concentrate in August across the Indianapolis, Fort Wayne, and Evansville metros. The Ohio River corner around Evansville runs warmer and longer than the rest of the state, with 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 Wabash, White, and Ohio River bottomlands. Hoosier National Forest hollows run a week or two behind the metros on phenology.
Monthly Biting Intensity (Midwest)
Indiana Mosquito Risk Profile
- WNV burden level
- Moderate
- about 30 to 60 confirmed cases annually
- EEE risk
- Rare
- Peak biting season
- late May through September
- Top urban risk areas
- Indianapolis (Marion)
- Fort Wayne (Allen)
- Evansville (Vanderburgh)
- South Bend (St. Joseph)
Signature habitat: Wabash River bottomlands, Ohio River floodplain, Hoosier National Forest swamps.
Climate driver: Southern Indiana borders Aedes albopictus range; northern Indiana stays Culex-dominated.
Check Your Local Mosquito Risk
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Common Mosquitoes in Indiana
Understanding which mosquitoes are active in Indiana 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 Indiana
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.
When does mosquito season end in Indiana?
Mosquito activity winds down after the first hard freeze, which in Indiana typically arrives around Oct 16. See the local first-frost window and city-by-city freeze dates.
Indiana first frost datesAlso worried about ticks in Indiana?
Lyme disease risk and tick activity track different seasonal patterns than mosquitoes. See your Indiana tick forecast.
View Indiana tick forecastStay Safe in Indiana
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