Long Island Mosquito Activity Index
Seasonal mosquito activity estimates for Suffolk County, Nassau County, and all Long Island regions — based on temperature, humidity, rainfall patterns, and typical seasonal pressure.
This is a seasonal activity estimate based on historical Long Island mosquito patterns and current weather conditions. It is not a live government surveillance feed or health advisory.
Activity by Region
Five Long Island regions, updated seasonally.
Suffolk County
Warm temperatures and recent rain events have produced favorable breeding conditions across western and central Suffolk. Coastal marsh communities and areas near retention basins are seeing the heaviest pressure.
Elevated activity in:
Nassau County
Nassau County is experiencing moderate seasonal activity. South Shore bay communities near Jones Beach and the bays see elevated pressure. North Shore suburban areas are reporting typical mid-season conditions.
Elevated activity in:
North Shore
The North Shore's wooded terrain, larger residential lots, and shaded canopy create sustained mosquito habitat. Humidity from Long Island Sound contributes to elevated daytime activity.
Elevated activity in:
South Shore
The South Shore consistently sees the highest mosquito pressure on Long Island. Saltmarsh mosquitoes from Great South Bay, canal communities, and barrier island terrain create conditions that peak in mid-summer.
Elevated activity in:
East End
The East End experiences significant mosquito pressure from Peconic Bay wetlands, freshwater ponds, and wooded property buffers. Southampton and East Hampton see the heaviest seasonal conditions.
Elevated activity in:
Why Mosquito Activity Is High on Long Island
Long Island's geography, climate, and development patterns create near-ideal conditions for mosquito populations through a long seasonal window.
Rainfall & Standing Water
Every inch of rain creates new breeding sites. Long Island's flat terrain, tidal marshes, and suburban containers hold standing water for the 7–10 days mosquitoes need to complete a breeding cycle.
Temperature
Mosquitoes are most active between 70–95°F. Long Island summers consistently produce months of peak breeding temperatures from June through August.
Humidity
High relative humidity — common on Long Island due to ocean and bay influence — extends mosquito activity into daytime hours and increases breeding success rates.
Seasonal Pressure
Peak season runs May through September. The first two to three weeks after the first warm rain of the season typically produce the sharpest population increases.
What Makes Long Island Different
South Shore Saltmarsh Mosquitoes
The Great South Bay, saltmarshes, and canal communities along the South Shore produce a distinct species — the saltmarsh mosquito (Coquillettidia perturbans) — that emerges in enormous numbers and travels farther than most species. Properties within several miles of Great South Bay and its barrier beaches experience this pressure.
South Shore locationsNorth Shore Wooded Terrain
The North Shore's bluffs, wooded neighborhoods, and larger residential lots create sustained mosquito and tick habitat. Tree canopy holds moisture and provides adult mosquito resting habitat. The combination of standing water, humidity, and tick-carrying deer makes North Shore properties among the most complex to manage.
North Shore locationsContainer Breeding in Suburbs
Nassau County and western Suffolk County's high-density suburban neighborhoods are hotspots for Aedes albopictus, the Asian tiger mosquito. This species breeds in very small amounts of water — bottle caps, clogged gutters, toys, and tarps. A single backyard can harbor dozens of breeding sites.
Find your townEast End Pond & Wetland Pressure
The East End's abundance of freshwater ponds, wetland areas, and agricultural drainage creates high breeding habitat density. Southampton, East Hampton, and Riverhead see significant late-summer pressure as Culex pipiens populations peak near ponds and irrigation systems.
East End locationsShould You Treat This Week?
Recommendations based on current activity levels across Long Island.
Low Activity — Conditions are calm — stay prepared.
Mosquito activity is below seasonal average. Focus on eliminating standing water sources and maintain awareness as conditions can change quickly after rain.
Preventative measures recommended.
Moderate Activity — Mosquito activity may increase following rainfall.
Moderate activity has been observed. Homeowners with outdoor entertainment areas, pools, or pets may benefit from preventative barrier treatment before activity peaks.
Consider preventative treatment.
High Activity — Conditions are favorable for mosquito activity.
High activity is present across the region. Homeowners with outdoor living areas, young children, or pets will likely notice increased mosquito encounters. Professional treatment is strongly recommended.
Treatment recommended this week.
Very High Activity — Peak activity — treatment is strongly recommended.
Conditions have reached peak seasonal levels. Standing water, high humidity, and sustained warmth have created the highest-pressure period of the year. Untreated properties will experience significant mosquito activity.
Treatment strongly recommended — contact Pestify.
Explore More
Tick Activity Index
Deer tick and blacklegged tick seasonal estimates.
Mosquito Map
Town-by-town activity across Long Island.
Monthly Reports
June through September detailed reports.
Forecast Page
Current conditions for Suffolk and Nassau.
Backyard Risk Quiz
Assess your specific property's risk level.
Find Your Town
Location-specific mosquito and tick guides.
Ready to Protect Your Property?
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