Today's Mosquito Risk in Delaware: 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 5 to 15 confirmed cases annually
- Based on CDC ArboNET surveillance data
- Risk Tier
- Tier 3: Moderate
- Salt-marsh mosquito (Ae. sollicitans) dominates beach-town biting.
- Per mosquito-risk-model regional tier
- Highest-Risk Areas
- New Castle (WNV); Sussex (salt marsh and EEE)
Current Situation in Delaware
Delaware packs salt marsh, agricultural Culex, and coastal cedar swamps into a small footprint, with WNV burden running about 5 to 15 confirmed human cases annually. Wilmington and the New Castle County suburbs carry most of the urban Cx. pipiens load, while Sussex County's beach towns get hammered by Aedes sollicitans saltmarsh biting from Memorial Day through September. The Cypress Swamp on the Maryland border and Bombay Hook National Wildlife Refuge along the Delaware Bay produce sustained mixed Culex and Aedes populations. EEE is rare but documented in Sussex County swamps. Aedes albopictus is established statewide. Biting season runs June through early October.
Snapshot of the current mosquito situation in Delaware, drawn from CDC ArboNET surveillance and the regional risk model.
- Risk Level
- Low
- Peak Activity
- May through September
- Dominant Vector
- Northern House Mosquito (Culex pipiens)
Where Mosquitoes Breed in Delaware
Delaware mosquito habitat is built on Delaware Bay salt marsh, the agricultural Culex grid of Kent and Sussex counties, and pockets of inland cedar swamp. Salt marsh from Bombay Hook NWR south through Prime Hook NWR and along the Atlantic coast at Cape Henlopen produces the saltmarsh mosquito that drives beach-town biting. The Great Cypress Swamp on the Maryland border holds Culiseta and woodland Aedes populations. Storm drains across Wilmington, Newark, and Dover sustain the urban Cx. pipiens, and the Nanticoke River marshes round out the mix.
Hotspot Counties & Areas
- New Castle County (Wilmington, Newark urban Culex)
- Kent County (Dover, agricultural Culex)
- Sussex County (beach towns, salt marsh biting)
- Bombay Hook National Wildlife Refuge
- Prime Hook National Wildlife Refuge
- Great Cypress Swamp (Sussex-Maryland border)
- Nanticoke River corridor
Seasonal Activity Pattern
Biting starts in early June, peaks late July through August, and tapers through September with stragglers into early October. WNV cases land in August across New Castle County and the Dover metro. Aedes sollicitans biting in Rehoboth, Bethany, and Lewes spikes hard around full-moon high tides that flood the back marsh, and the worst stretches run from late June through Labor Day. Aedes albopictus daytime biting in suburban yards across Wilmington and Newark runs from July through early October.
Monthly Biting Intensity (Mid-Atlantic)
Delaware Mosquito Risk Profile
- WNV burden level
- Low
- about 5 to 15 confirmed cases annually
- EEE risk
- Rare; documented in Sussex County swamps
- Peak biting season
- June through early October
- Top urban risk areas
- Wilmington (New Castle)
- Dover (Kent)
- Newark (New Castle)
Signature habitat: Delaware Bay salt marsh, agricultural Culex, Cypress Swamp.
Climate driver: Salt-marsh mosquito (Ae. sollicitans) dominates beach-town biting.
Check Your Local Mosquito Risk
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Common Mosquitoes in Delaware
Understanding which mosquitoes are active in Delaware helps you identify threats and take appropriate precautions. Click any card for details.
Asian Tiger Mosquito
Aedes albopictus
Risk: Eastern Equine Encephalitis, dengue, chikungunya, Zika, dog heartworm.
Key feature: A single bright white stripe down the center of the back.
Active: Spring through first hard frost. Eggs overwinter in cold climates and hatch when flooded by spring rain.
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.
Eastern Equine Encephalitis
Vector: Asian Tiger Mosquito
Eastern Equine Encephalitis
Rare but devastating, with roughly 30% case fatality. Concentrated in Northeast swamp areas and the Gulf Coast.
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 Delaware
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 Delaware?
Mosquito activity winds down after the first hard freeze, which in Delaware typically arrives around Oct 28. See the local first-frost window and city-by-city freeze dates.
Delaware first frost datesAlso worried about ticks in Delaware?
Lyme disease risk and tick activity track different seasonal patterns than mosquitoes. See your Delaware tick forecast.
View Delaware tick forecastStay Safe in Delaware
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