New Jersey · Mosquito Season Guide

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II. New Jersey Mosquito Season Month by month

New Jersey has had organized county mosquito control since 1914 — the oldest program in the United States. More than a century of coordinated effort has reduced nuisance biting significantly across much of the state, but three problems persist: Culex pipiens WNV transmission in the urban north, salt marsh mosquitoes on the Shore, and EEE eruptions in the Pine Barrens.

Very Low Low Moderate High Very High taller = more active · color = severity

Chart reflects northern New Jersey / Newark baseline. The Shore and southern NJ (Atlantic, Cape May counties) can be significantly higher in nuisance biting due to salt marsh species, particularly after coastal events.

~63

mosquito species recorded in New Jersey

1914

year NJ organized the first county mosquito control program in the US

May–Sep

typical active season — Shore salt marsh season can start earlier

counties — all with organized mosquito control programs

A century of control — and three problems that persist

New Jersey has invested more in organized mosquito control per square mile than virtually any state in the country. Every county has its own mosquito control commission; crews inspect catch basins, ditches, and wetlands; biological larvicide (Bti) is applied by air and ground throughout the season. The results are real — without this infrastructure, NJ's dense population, extensive tidal wetlands, and humid summers would produce far worse conditions. But control has its limits. Culex pipiens WNV transmission in the Newark/Trenton metro corridor remains an annual event, EEE surfaces in the Pine Barrens most seasons, and salt marsh mosquitoes at the Shore are more of a natural phenomenon than a control problem.

The Pine Barrens: EEE country

Burlington, Ocean, and Atlantic counties — covering much of the Pine Barrens — are the core EEE zone in New Jersey. The Pinelands' forested swamps and boggy cedar wetlands create ideal breeding conditions for Culiseta melanura, the primary EEE amplifier. EEE activity is detected in NJ surveillance traps most seasons; human cases occur irregularly but carry a high fatality risk. The New Jersey Department of Health (NJDOH) issues county-level EEE risk advisories based on weekly trap data, and aerial spray operations are sometimes deployed in Burlington County during high-risk periods.

The Shore: salt marsh mosquitoes

Coastal counties — Ocean, Monmouth, Atlantic, Cape May — host significant populations of Aedes sollicitans (salt marsh mosquito) and related species. These breed in tidal salt marshes that fringe the barrier islands and mainland shore. Salt marsh mosquitoes are aggressive, wide-ranging biters — adults can travel several miles from their breeding sites, making control difficult. Shore visitors experience this as relentless outdoor biting in evening hours from June through September. County mosquito commissions apply mosquito-control ditches and larvicide in salt marshes, but the sheer acreage limits effectiveness.

III. New Jersey's Three Species to Know

Culex pipiens

Northern House Mosquito · ⚠ West Nile Vector

The dominant mosquito in the Newark/Jersey City metro, across suburban North Jersey, and in the Trenton corridor. Breeds in stagnant water — storm drains, catch basins, birdbaths, standing containers. Feeds at dusk and overnight, shifting from birds to humans in late summer. WNV is detected in NJ Cx. pipiens surveillance pools every season; Essex, Hudson, Middlesex, and Mercer counties historically carry the highest burden. NJDOH weekly trap reports are the best indicator of elevated local risk.

Aedes vexans — used here as representative of the salt marsh mosquito complex

Aedes sollicitans

Salt Marsh Mosquito · Shore Pest

The signature species along the New Jersey Shore. Breeds in coastal salt marshes — vast tidal flats that fringe the barrier islands and back bays from Sandy Hook to Cape May. An aggressive daytime and evening biter that can travel several miles from breeding sites, making it the dominant annoyance mosquito for Shore visitors and residents. Not a significant disease vector, but responsible for most of the memorable biting misery at the Shore from June through September. County control programs treat marshes with Bti but cannot eliminate such extensive habitat.

Aedes albopictus

Asian Tiger Mosquito

Well established across all of New Jersey and one of the primary daytime nuisance biters in suburban yards statewide. Visually distinctive: black with bold white stripes. Bites aggressively during daylight — especially morning and late afternoon — making it the mosquito suburban NJ residents encounter most often in their own backyards. Breeds in tiny water volumes: bottle caps, gutters, tarps, saucers under pots. NJ's density and heavy rainfall support large populations. Eliminating container water weekly is the most effective control available to homeowners.

EEE is present in NJ surveillance traps most seasons. If you're camping or hiking in the Pine Barrens (Burlington, Ocean, Atlantic counties), or near forested wetlands anywhere in southern NJ, take dusk and dawn precautions seriously during mosquito season. Check current NJDOH EEE risk advisories →

IV. City-by-City Reference

City	Active Season	Off-Season	Notes	Live data
Newark	May – Sep	Near-zero Oct–Apr	Essex County; Culex pipiens dominant; urban density and storm drain infrastructure favor WNV breeding; Ae. albopictus well established in neighborhoods; Passaic River corridor; NJDOH and Essex County Mosquito Control coordinate WNV surveillance; highest urban WNV risk in state	Check live
Jersey City	May – Sep	Near-zero Oct–Apr	Hudson County; high urban density; WNV detected in Hudson County traps most seasons; limited open water habitat limits absolute population size but Cx. pipiens exploits every available container and drain; Ae. albopictus common in residential blocks	Check live
Trenton	May – Sep	Off Oct–Apr	Mercer County; Delaware River corridor; floodplain habitat amplifies Ae. vexans after heavy rain; WNV detected in Mercer County traps regularly; state capital — NJDOH publishes surveillance data here; Ae. albopictus present	Check live
Atlantic City	May – Sep	Off Oct–Apr	Atlantic County; surrounded by salt marsh habitat — Aedes sollicitans pressure can be intense from June through September; back bay marshes around the barrier islands are primary breeding habitat; county mosquito control conducts extensive salt marsh treatment; EEE detected in Atlantic County surveillance most seasons	Check live
Camden	May – Sep	Off Oct–Apr	Camden County; Delaware River; adjacent to Burlington County (core EEE zone) — check NJDOH EEE advisories; Culex pipiens and Ae. albopictus dominant in urban/suburban areas; South Jersey season slightly longer than North Jersey	Check live
Morristown	May – Sep	Off Oct–Apr	Morris County; inland / northern NJ; forested suburban terrain; Ae. albopictus very well established and the dominant nuisance species; WNV risk lower than urban counties; lower EEE risk than Pine Barrens; wooded lots and leaf litter piles support container breeders	Check live
Cherry Hill	May – Sep	Off Oct–Apr	Camden County; South Jersey suburb; proximity to Burlington and Atlantic county EEE zones — check advisories in high-risk years; Ae. albopictus and Cx. pipiens dominant; dense suburban landscaping favors container breeding; season slightly longer than North Jersey	Check live

More State Guides

Florida Year-round activity in the south — 80+ species including invasive Ae. aegypti and the Asian tiger mosquito across all 67 counties Texas ~85 species across four climate zones — Gulf Coast active March through November, with year-round pressure in the Rio Grande Valley California Central Valley is the #1 West Nile corridor in the US — invasive Ae. aegypti and Ae. albopictus now established in 20+ counties Georgia Atlanta metro leads the Southeast in Asian tiger mosquito density — active statewide March through November New York Ground zero for West Nile in the US (1999 Queens outbreak) — NYC metro and Long Island see the highest Northeast seasonal pressure Illinois Home of the 2002 Cook County West Nile outbreak — the deadliest urban WNV event in US history — peak season June through September Ohio Lake Erie to the Ohio River — WNV active in Franklin and Cuyahoga counties, with floodwater species surging after summer storms Pennsylvania Philadelphia WNV corridor meets rural EEE risk in western PA — the densest human population in the mid-Atlantic mosquito belt Michigan Site of the 2019 EEE outbreak — the deadliest in decades — 10 human cases and 6 deaths concentrated in SW Michigan Great Lakes wetlands Virginia Tidewater season runs April–October — the longest mid-Atlantic window — with the Great Dismal Swamp as an active EEE hotspot North Carolina The coastal plain runs one of the longest seasons in the Southeast — NC leads the nation in La Crosse encephalitis cases from the Appalachian foothills Maryland Chesapeake Bay watershed creates extraordinary mosquito habitat — tidal marshes, Eastern Shore wetlands, and the DC-Baltimore corridor combine for dense seasonal pressure Tennessee Memphis and the Mississippi River corridor historically record the highest WNV case counts in the mid-South — Ae. albopictus has colonized all 95 counties Indiana Indiana sits at the crossroads of the Great Lakes EEE belt — Lake Michigan wetlands in the north and the Wabash River floodplain drive intense seasonal pressure Louisiana The Gulf Coast's most intense pressure — coastal marshes and summer rains keep Cx. quinquefasciatus and Ae. aegypti active from March through November Alabama Mobile Bay to the Tennessee Valley — Ae. albopictus has reached all 67 counties and peak WNV season runs June through September South Carolina Low Country marshes produce some of the Southeast's densest Anopheles and Culex populations — season runs March through November Minnesota 10,000 lakes means 10,000 breeding sites — the Northwoods sees intense but short July–August peaks, while the Twin Cities face a longer June–September window Wisconsin Great Lakes wetlands and the 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 — season May through October Arkansas Delta rice-field flooding and the Arkansas River bottomlands create some of the highest rural mosquito pressure in the mid-South — active April through October Washington Western WA stays mild and damp year-round; the Yakima Valley and Columbia Basin face the highest WNV risk in the Pacific Northwest — peak July through September Arizona Monsoon season (July–September) drives sudden mosquito explosions across the Valley of the Sun — WNV detected annually Colorado Front Range WNV corridor stretches Denver to Fort Collins — eastern plains carry the state's highest risk Connecticut Connecticut River valley WNV pressure meets EEE risk in inland freshwater wetlands — active May through October Delaware Chesapeake and Delaware Bay marshes create outsized pressure for the nation's second-smallest state Hawaii Year-round activity at sea level — no native species, but Ae. aegypti and tiger mosquitoes established statewide Idaho Snake River Plain irrigation districts fuel summer WNV pressure — season June through September Iowa Mississippi River corridor and prairie wetlands drive intense June–September pressure — WNV active statewide Kansas Great Plains WNV corridor — Wichita and Kansas City see peak pressure July–August; floodwater species surge after storms Kentucky Ohio River corridor and Kentucky Lake wetlands sustain a long April–October season across all 120 counties Maine Short but intense July–August season — EEE detected in some years in the southern coastal plain Massachusetts EEE fatality rate exceeds 30% — the Plymouth County swamp complex is the active epicenter — season May through October Mississippi Gulf Coast near-year-round pressure meets Delta rice-field flooding for one of the South's most intense mosquito environments Montana Yellowstone and Missouri River corridors drive a compressed June–August season — WNV detected most years in eastern MT Nebraska Platte River valley and eastern Nebraska are among the Great Plains' most active WNV zones — peak July–August Nevada Las Vegas monsoon season drives July–September activity; Reno irrigation districts fuel a parallel northern peak New Hampshire EEE detected most years — the southern lakes and coastal plain are in the active Northeast EEE corridor New Mexico Monsoon season (July–September) creates sudden breeding habitat; WNV circulates in the Rio Grande valley annually North Dakota Red River Valley flooding produces some of the Great Plains' most extreme floodwater mosquito events — peak June–August Oklahoma One of the South-Central's most intense seasons — the Arkansas and Red River corridors sustain populations April through October Oregon Eastern Oregon Columbia Basin is the state's WNV hotspot; western Oregon runs a mild coastal season June through September Rhode Island New England's densest coastal pressure — Narragansett Bay salt marshes and WNV active in all five counties South Dakota Missouri River and James River valleys drive summer WNV activity — eastern SD sees the most intense pressure Utah Salt Lake Valley WNV corridor and irrigation districts sustain a July–September peak — drier areas see limited activity Vermont Champlain Valley runs Vermont's longest season — EEE detected in the Lake Champlain lowlands in some years West Virginia Kanawha and Ohio River valleys sustain a May–October season — Ae. albopictus now established statewide Wyoming The shortest meaningful season of any contiguous US state — North Platte valley WNV window is just 6–8 weeks

West Nile, dengue, and EEE: US disease risk by region → Asian tiger mosquitoes: why you're getting bitten during the day → Eliminating standing water: the highest-leverage yard move →