Today's Mosquito Risk in Maryland: 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
- Chesapeake salt marsh plus humid summers sustain steady WNV transmission.
- Per mosquito-risk-model regional tier
- Highest-Risk Areas
- Baltimore City, Montgomery, Prince George's (WNV); Dorchester and Worcester (salt marsh)
Current Situation in Maryland
Maryland's mosquito profile is anchored by Chesapeake Bay salt marsh, the Patuxent and Potomac floodplains, and the urban Culex grid of Baltimore and the DC suburbs. WNV burden runs roughly 30 to 60 confirmed human cases annually, with most concentrated in Baltimore City, Montgomery County, and Prince George's County. Aedes albopictus is established statewide and dominates daytime suburban biting. The Eastern Shore counties of Dorchester, Wicomico, and Worcester produce massive Aedes sollicitans saltmarsh hatches off Blackwater NWR and the Assateague Island marshes. EEE is rare. Biting season runs late May through early October, peaking in August.
Snapshot of the current mosquito situation in Maryland, drawn from CDC ArboNET surveillance and the regional risk model.
- Risk Level
- Moderate
- Peak Activity
- May through September
- Dominant Vector
- Northern House Mosquito (Culex pipiens)
Where Mosquitoes Breed in Maryland
Maryland mosquito habitat is dominated by Chesapeake Bay tidal marsh and the floodplains of the Patuxent and Potomac rivers. Eastern Shore salt marsh across Dorchester, Wicomico, and Worcester counties, including Blackwater NWR and Assateague Island, produces Aedes sollicitans and Culex salinarius. The Patuxent River bottomlands and the Potomac floodplain through Charles and Prince George's counties sustain dense Aedes vexans hatches after summer storms. Baltimore rowhouse alleys, abandoned pools, and storm drains carry the urban Cx. pipiens load. Suburban Montgomery and Howard counties hold steady Aedes albopictus populations in backyard containers.
Hotspot Counties & Areas
- Baltimore City (urban Culex, rowhouse alleys)
- Montgomery County (DC suburb albopictus, Rockville)
- Prince George's County (Patuxent floodplain)
- Anne Arundel County (Annapolis, Bay shoreline)
- Frederick County (agricultural Culex, Monocacy)
- Dorchester County (Blackwater NWR salt marsh)
- Worcester County (Assateague Island, Ocean City marsh)
- Charles County (Potomac floodplain)
Seasonal Activity Pattern
Biting starts in late May in the Bay Bridge corridor, peaks late July through August, and tapers through September. WNV cases concentrate in August across Baltimore, Montgomery, and Prince George's counties. Aedes sollicitans biting on the Eastern Shore spikes around full-moon high tides that flood the back marsh, and Assateague Island campers get hit hardest from June through September. Heavy summer storms produce 1 to 2 week floodwater Aedes vexans pulses along the Patuxent and Potomac.
Monthly Biting Intensity (Mid-Atlantic)
Maryland Mosquito Risk Profile
- WNV burden level
- Moderate
- about 30 to 60 confirmed cases annually
- EEE risk
- Rare
- Peak biting season
- late May through early October
- Top urban risk areas
- Baltimore (Baltimore City)
- Silver Spring (Montgomery)
- Frederick (Frederick)
- Annapolis (Anne Arundel)
Signature habitat: Chesapeake Bay salt marsh, Patuxent and Potomac floodplains, urban Baltimore Culex.
Climate driver: Chesapeake salt marsh plus humid summers sustain steady WNV transmission.
Check Your Local Mosquito Risk
Ready to see current mosquito activity in your area? Get today's forecast and personalized risk assessment for your ZIP code.
Common Mosquitoes in Maryland
Understanding which mosquitoes are active in Maryland 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 Maryland
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 Maryland?
Mosquito activity winds down after the first hard freeze, which in Maryland typically arrives around Oct 24. See the local first-frost window and city-by-city freeze dates.
Maryland first frost datesAlso worried about ticks in Maryland?
Lyme disease risk and tick activity track different seasonal patterns than mosquitoes. See your Maryland tick forecast.
View Maryland tick forecastStay Safe in Maryland
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