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When Does Mosquito Season Start? Complete Guide by State & Province

Your region-by-region cheat sheet to mosquito timing, peak months, and plant-powered protection — updated for 2026.

Here's a truth that surprises people every year: mosquito season doesn't start when you notice the first bite. By then, breeding populations are already established. Knowing exactly when mosquitoes wake up in your area means you can outsmart them before they even get started.

This guide breaks down mosquito season timing for every major region in the US and Canada — plus what drives those timelines, which diseases to watch for, and how to stay protected without harsh chemicals.

What Actually Triggers Mosquito Season?

Mosquitoes aren't checking a calendar — they're checking the thermostat:

Temperature What Happens
Below 50°F (10°C) Mosquitoes go dormant or die off. Winter reprieve!
50–60°F (10–15°C) Overwintering mosquitoes start waking up. Eggs begin hatching.
70–80°F (21–27°C) Prime time. Breeding cycles accelerate. Egg-to-adult in under 10 days.
Above 95°F (35°C) Activity decreases slightly but they shift to dawn/dusk feeding.

Add standing water and humidity, and you've got a mosquito factory. That's why warm, wet regions have the longest seasons.

United States Mosquito Season by Region

Florida

Season: February–November (South FL is nearly year-round)
Peak: June–October (rainy season)
Key risks: Dengue, Zika, West Nile Virus, Eastern Equine Encephalitis

With roughly 80 mosquito species, Florida has the longest and most intense mosquito season in the continental US. South Florida rarely gets a full break. The rainy season (June–October) is when things really escalate.

Read the full Florida Mosquito Season Guide

Texas

Season: March–November (varies by sub-region)
Peak: June–September
Key risks: West Nile Virus, Dengue (border areas)

Texas hosts 85 mosquito species — more than any other state. South Texas/Houston starts as early as March, while North Texas (Dallas-Fort Worth) kicks off in April.

Read the full Texas Mosquito Season Guide

Georgia & the Southeast

Season: March–November
Peak: June–September
Key risks: West Nile Virus

Atlanta has ranked as the #1 worst mosquito city in the US according to Orkin. Hot, humid summers combined with afternoon thunderstorms create perfect breeding conditions throughout the Southeast.

Read the full Southeast Mosquito Season Guide

California

Season: March–October (varies by sub-region)
Peak: June–September
Key risks: West Nile Virus, occasional local Dengue

Five California cities rank in Orkin's Top 50 for mosquito activity: Los Angeles, San Francisco, Sacramento, San Diego, and Fresno. Irrigated landscapes create breeding sites even in dry regions.

Read the full California Mosquito Season Guide

New York

Season: Late April–October/November
Peak: July–August
Key risks: West Nile Virus

New York ranks in the top 5 mosquito cities nationwide. The first US West Nile Virus outbreak was identified in NYC in 1999, and the virus remains a concern statewide every summer.

Read the full New York Mosquito Season Guide

Louisiana

Season: March–November (nearly year-round)
Peak: May–October
Key risks: West Nile Virus (endemic), St. Louis Encephalitis

Louisiana's humid subtropical climate means mosquitoes are a near-permanent fixture. West Nile Virus has been endemic here since 2002.

The Carolinas (NC & SC)

Season: March–November
Peak: June–September
Key risks: West Nile Virus, EEE

Coastal marshes and inland humidity make both states prime mosquito territory. The Outer Banks and Lowcountry are particularly notorious during summer months.

The Midwest (IL, OH, MI, MN, WI)

Season: Late April–October
Peak: July–August
Key risks: West Nile Virus

Chicago, Detroit, and Cleveland all made Orkin's top 10 mosquito cities. Lake-effect weather and summer rain create ideal breeding conditions throughout the Great Lakes region.

Pacific Northwest (WA & OR)

Season: May–September
Peak: July–August
Key risks: West Nile Virus (lower risk)

Shorter season, but wet conditions in low-lying areas can make it intense. Camping and hiking season overlaps perfectly with mosquito peak.

Mid-Atlantic (VA, MD, DC)

Season: April–October
Peak: June–August
Key risks: West Nile Virus

DC's famous humidity is mosquito paradise. Suburban yards, wooded parks, and waterfront areas are all hotspots.

Colorado

Season: May–September
Peak: June–August
Key risks: West Nile Virus

Denver recently broke into Orkin's top 10. Plains and river valleys are significantly worse than mountain communities, where cooler temps limit activity.

Arizona & Nevada

Season: March–October
Peak: July–September (monsoon season)
Key risks: West Nile Virus

Desert mosquitoes? Yep. Monsoon rains create temporary pools that breed mosquitoes rapidly. Cities with irrigated landscapes — Phoenix, Las Vegas — are more affected than you'd expect.

Hawaii

Season: Year-round
Peak: Wet season (November–March)
Key risks: Dengue

Hawaii has no true mosquito off-season. The tropical climate supports activity all year, with the wet season intensifying things. Repellent is non-negotiable for travelers.

Canada Mosquito Season by Province

Mosquitoes are active in every Canadian province and territory. They generally emerge when temperatures hit 7–16°C (about 45–60°F), which typically falls in April or May depending on your region.

Ontario

Season: May–September/October
Peak: June–August
Key risks: West Nile Virus (Toronto area surveillance active)

Ontario is home to 67 mosquito species. Cottage country, parks, and urban greenspaces all see significant activity. Toronto Public Health sprays catch basins starting in early June each year.

Read the full Ontario Mosquito Season Guide

British Columbia

Season: May–September
Peak: June–August
Key risks: West Nile Virus (low but present)

The BC Interior and Okanagan tend to be worse than the Lower Mainland coast. Camping, hiking, and lake activities put you right in peak exposure territory.

Read the full BC Mosquito Season Guide

Alberta

Season: Late May–September
Peak: July–August
Key risks: West Nile Virus (expanding)

Calgary is home to 20 of Alberta's 44 known mosquito species. The season is short but can be fierce, especially after snowmelt and heavy spring rain.

Quebec

Season: May–September
Peak: June–August
Key risks: West Nile Virus (detected in bird populations)

Similar timing to Ontario. Laurentians, Eastern Townships, and cottage regions all see heavy summer activity.

Manitoba & Saskatchewan

Season: May–September
Peak: June–August
Key risks: West Nile Virus (among highest per-capita rates in Canada)

Winnipeg has earned a reputation as Canada's unofficial mosquito capital. Aggressive floodwater species and flat, wet terrain make the prairies one of the most intense mosquito regions in the country.

How to Protect Yourself — Without the Harsh Stuff

Do This Skip This
Use a plant-based repellent with proven ingredients like PMD Relying on citronella candles alone — they don't cut it
Eliminate standing water on your property weekly Waiting until you see mosquitoes to start prevention
Wear loose, light-colored clothing at dawn/dusk Skipping repellent because “it's not that bad yet”
Apply repellent before you go outside, not after the first bite Using DEET-based products on babies and young children
Choose a repellent that's safe for kids 6+ months and skin-friendly Bug zappers — they actually attract more mosquitoes to your yard

Ready to bloc mosquitoes the plant-powered way?

The Superbloc's Bloc Off and Bloc Chill repellents use PMD from lemon eucalyptus — lab-tested for 6 hours of protection, DEET-free, alcohol-free, and safe for babies 6+ months.

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