IsItMosquitoSeasonYet
Guides

Mosquito guides

Evidence-based answers — from why you get bitten more than your partner to where mosquito season is heading as species ranges shift.

The species in your yard determines when it bites, what diseases it might carry, and how to protect yourself. Different species, different strategies.

Species · Invasive

Yellow fever mosquito (Ae. aegypti)

The Gulf Coast's dengue and Zika vector — a daytime biter that breeds in the clean water containers around your home. Established year-round in South Florida, coastal Texas, and now spreading into California.

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Species · Native

Southern house mosquito (Cx. quinquefasciatus)

The dusk biter that ruins summer evenings across the South — and the primary West Nile vector in Florida, Texas, Georgia, and California. The classic "patio mosquito."

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Species · Native

Common house mosquito (Cx. pipiens)

The northern city mosquito behind the 1999 West Nile outbreak in New York — it overwinters in basements, breeds in clogged gutters, and is the dominant WNV vector from Ohio to New England.

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Species · Native

Inland floodwater mosquito (Ae. vexans)

The swarms that appear days after heavy rain — eggs survive years in dry soil, then hatch within hours of flooding. Found coast-to-coast, with documented flight ranges of 5–10 miles.

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Species · Invasive

Asian bush mosquito (Ae. japonicus)

A cold-tolerant invasive from Japan, now established across the Northeast and Midwest — the only invasive Aedes that can efficiently transmit West Nile. Found at elevations no other invasive can reach.

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Species · Native

Western encephalitis mosquito (Cx. tarsalis)

The most medically dangerous mosquito most Westerners have never heard of — the primary West Nile and Western equine encephalitis vector across California, Nevada, and the Great Plains.

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Live activity levels, peak months, local species, and city-by-city breakdowns — updated with real weather data.

Florida
Season runs nearly year-round in the south — 80+ species, two that bite during the day
Texas
~85 species across four climate zones — Gulf Coast active March through November
California
Central Valley is the #1 West Nile corridor in the US — invasive Ae. aegypti in 20+ counties
Georgia
Atlanta metro is the top Asian tiger mosquito city in the Southeast — active March through November statewide
New York
WNV was first detected in the Western Hemisphere in Queens in 1999 — Culex pipiens dominates the metro
Illinois
Home of the 2002 Cook County West Nile outbreak — the deadliest urban WNV event in US history
Ohio
Lake Erie to the Ohio River — WNV in Franklin and Cuyahoga counties, floodwater surges after storms, ~60 species
Pennsylvania
Philadelphia metro rivals New York for mid-Atlantic pressure — Pittsburgh river valleys extend the season, ~60 species
Michigan
EEE hotspot state — Lower Peninsula marshes drive intense July–August pressure; inland lakes amplify breeding across both peninsulas
North Carolina
Coastal plain season starts 3–4 weeks before the mountains — leads the nation in La Crosse encephalitis from Appalachian foothills
Virginia
Tidewater season runs April–October — the Great Dismal Swamp is one of the East Coast's most active EEE hotspots
New Jersey
Most aggressive mosquito control program in the US — 19 county agencies, yet coastal salt marshes still drive intense summer pressure
Maryland
Chesapeake Bay tidal marshes and Eastern Shore wetlands create some of the densest mid-Atlantic habitat — Baltimore corridor peaks June–August
Tennessee
West Tennessee and the Memphis corridor is the state's primary West Nile zone — Smoky Mountains see a shorter but still active summer season
Indiana
Lake Michigan wetlands in the north host EEE surveillance zones — central Indiana corn country drives floodwater species surges after heavy rain
Louisiana
Near-year-round bayou activity — coastal marshes keep Cx. quinquefasciatus and Ae. aegypti active from March through November
Alabama
Gulf Coast activity starts as early as February — Ae. albopictus has reached all 67 counties and peak WNV season runs June through September
South Carolina
Low Country tidal marshes produce some of the Southeast's densest populations — season runs March through November statewide
Minnesota
10,000 lakes means 10,000 breeding sites — the June–August peak is among the most intense short-season windows in North America
Wisconsin
Great Lakes wetlands and Mississippi River backwaters drive strong WNV pressure in the Milwaukee corridor — peak season July through August
Missouri
At the confluence of the Missouri and Mississippi rivers — St. Louis historically ranks among the highest WNV cities in the US
Arkansas
Delta rice-field flooding and the Arkansas River bottomlands create extraordinary floodwater mosquito density — one of the most underrated mosquito states
Washington
Eastern WA Columbia Basin is a major West Nile Virus zone — western WA runs a moderate coastal season June through September
Mississippi
Gulf Coast near-year-round pressure meets Delta rice-field flooding — one of the South's most intense mosquito environments
Oklahoma
One of the South-Central's most intense seasons — Arkansas and Red River corridors sustain populations April through October
Kentucky
Ohio River corridor and Kentucky Lake wetlands sustain a long April–October season — Ae. albopictus established across all 120 counties
Iowa
Mississippi River corridor and prairie pothole wetlands drive intense June–September pressure — WNV active statewide in most years
Kansas
Great Plains WNV corridor — Wichita and Kansas City see peak pressure July–August, floodwater species surge in the Arkansas River basin
Nebraska
Platte River valley and eastern Nebraska are among the Great Plains' most active West Nile zones — peak pressure July through August
West Virginia
Kanawha and Ohio River valleys sustain a May–October season — Ae. albopictus now established statewide and bites throughout the day
Arizona
Monsoon season (July–September) creates sudden mosquito explosions across the Valley of the Sun — WNV detected annually in Maricopa County
Colorado
Front Range WNV corridor stretches Denver to Fort Collins — eastern plains irrigation districts carry the state's highest risk, peak July–August
Massachusetts
EEE kills more than 30% of human cases — the Plymouth County swamp complex is the active Northeast epicenter — season May through October
Connecticut
Connecticut River valley WNV pressure meets inland EEE risk — one of the densest seasonal mosquito corridors in New England
Oregon
Eastern Oregon Columbia Basin is the state's WNV hotspot — western Oregon runs a mild but persistent coastal season June through September
North Dakota
Red River Valley flooding produces some of the Great Plains' most extreme floodwater mosquito events — the June–August peak can be severe
South Dakota
Missouri River and James River valleys drive summer WNV activity — eastern SD sees the most intense pressure of any part of the state
New Hampshire
EEE detected most years — the southern lakes and coastal plain sit squarely in the active Northeast EEE corridor, season June through September
Delaware
Chesapeake and Delaware Bay marshes create outsized pressure for the nation's second-smallest state — Rehoboth Beach coastal season runs April through October
Idaho
Snake River Plain irrigation districts fuel summer WNV pressure — season June through September, with Cx. tarsalis as the primary vector
Montana
Yellowstone and Missouri River corridors drive a compressed June–August season — WNV detected most years in eastern Montana agricultural areas
Utah
Salt Lake Valley WNV corridor and irrigation districts sustain a July–September peak — the Great Salt Lake wetlands are a surprisingly active habitat
Nevada
Las Vegas monsoon season drives July–September activity — Reno irrigation districts produce a parallel WNV season in northern Nevada
New Mexico
Monsoon season (July–September) creates sudden breeding habitat — WNV circulates in the Rio Grande valley annually, Ae. aegypti present in southern cities
Maine
Short but intense July–August season — coastal and southern Maine sit on the edge of the Northeast EEE corridor, with WNV present most years
Vermont
Champlain Valley runs Vermont's longest season — Lake Champlain lowlands have EEE surveillance activity and WNV detected most years
Rhode Island
New England's densest coastal pressure — Narragansett Bay salt marshes and WNV active in all five counties every season
Hawaii
Year-round activity at sea level — no native mosquito species, but Ae. aegypti and tiger mosquitoes are established statewide and bite during the day
Wyoming
The shortest meaningful season of any contiguous US state — North Platte valley WNV window is 6–8 weeks, centered on July