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Mississippi · Mosquito Season Guide

Is it mosquito season in Mississippi?

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II. Mississippi Mosquito Season Month by month

Mississippi is one of the most mosquito-active states in the nation. The Mississippi Delta — the flat alluvial floodplain between the Yazoo and Mississippi rivers — is among the most productive mosquito breeding environments in North America, with rice fields, oxbow lakes, and bayous providing near-perfect conditions. On the Gulf Coast, activity is essentially year-round. The only relief is altitude — which Mississippi largely lacks.

Jackson / Central Mississippi
Jackson · Hattiesburg · Meridian
Gulf Coast
Gulfport · Biloxi · Pascagoula
Very Low Low Moderate High Very High taller = more active · color = severity
~60
mosquito species recorded in Mississippi
Year-round
activity on the Gulf Coast
Delta
one of the most intense freshwater mosquito environments in North America
82
counties — all with seasonal exposure

The Mississippi Delta: extraordinary floodwater density

The Yazoo-Mississippi Delta — the flat agricultural counties from Tunica south to Vicksburg — is a mosquito ecologist's case study. Rice field flooding, the backwater lakes of the Yazoo basin, and warm temperatures from March through November combine to produce extraordinary Culex quinquefasciatus and Aedes vexans populations. West Nile Virus circulates through the Delta's large resident bird populations every summer.

The Gulf Coast: near-year-round activity

Hancock, Harrison, and Jackson counties along the Gulf of Mexico experience mosquito activity in every month of the year. January and February see the lowest pressure but not complete dormancy. The combination of coastal marshes, warm sea temperatures moderating winter cold, and summer humidity creates conditions that sustain year-round populations of Culex quinquefasciatus and Aedes aegypti.

Central and southern Mississippi: the long season

Jackson, Hattiesburg, and the central counties run a February-through-November effective season in most years. The Pearl, Pascagoula, and Tombigbee River watersheds provide extensive floodplain habitat. Aedes albopictus is established statewide and has made daytime biting pressure as significant as the nighttime Culex window.

III. Mississippi's Key Mosquito Species
Culex quinquefasciatus mosquito photograph
Culex quinquefasciatus
Southern House Mosquito

The Mississippi Delta's flooded rice fields, catfish ponds, and drainage ditches generate some of the densest Culex quinquefasciatus populations in the mid-South. The species colonizes warm, organically enriched standing water — anything from bayou edges to clogged storm drains in Jackson and Biloxi — and emerges at dusk to feed through the night. It drives essentially all WNV transmission in the state, with peak risk July through September.

Aedes aegypti mosquito photograph
Aedes aegypti
Yellow Fever Mosquito

Gulf Coast Mississippi sits at the northern edge of sustained Ae. aegypti territory — winters in Biloxi and Gulfport rarely dip hard enough to collapse resident populations the way they do inland. A strict daytime biter that breeds almost exclusively in small containers near homes, it is the primary dengue concern in the coastal plain during peak summer months. Its distribution tracks the coast; it thins out sharply north of Hattiesburg.

Aedes albopictus mosquito photograph
Aedes albopictus
Asian Tiger Mosquito

Inland Mississippi's dominant biter since the 1980s, when albopictus arrived via the used-tire trade and spread rapidly through the Southeast. It now blankets every county — from the Delta to the Piney Woods — breeding in old tires, clogged gutters, and ornamental plant saucers. Its four-month-plus biting window from April through November accounts for most of the daylight biting misery across residential areas, and it has largely displaced native container breeders in suburban habitat.

IV. Mississippi Cities at a Glance
CityPeak SeasonOff-SeasonNotes
Jackson Feb – Nov Off Dec–Jan Pearl River corridor; WNV active; above-average urban Culex quinquefasciatus pressure Check live
Gulfport Year-round Lighter Dec–Jan Gulf Coast marshes; year-round activity; Harrison County among most active in state Check live
Biloxi Year-round Lighter Dec–Jan Coastal bayous; Back Bay of Biloxi; near-constant pressure; Ae. aegypti present Check live
Hattiesburg Mar – Nov Off Dec–Feb Forrest County; Leaf River corridor; above-average suburban pressure Check live
Southaven Apr – Oct Off Nov–Mar DeSoto County; Memphis metro spillover; shorter season than coastal MS 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 New Jersey Oldest organized county mosquito control in the US (1914) — Pine Barrens EEE corridor and fierce salt marsh Shore species 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 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 →