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Fort Myers Mosquito Forecast

Today's mosquito activity in Fort Myers, the week ahead, and what to do about it. Updated hourly.

Bite Index · Sunday, November 8

Severe

Severe mosquito activity in Fort Myers today and easing through the week. Expect to be bitten within minutes outdoors at dusk.

Swarming conditions. Expect bites within a minute or two outside at dusk.

Worse than a typical November in Lee County (usually around 64).

  • Two weeks averaging 77°F is ideal breeding weather: egg to biting adult in about a week.
  • Tonight: a 74°F evening, light wind — good flying weather for mosquitoes.
  • 0.8 in. of rain Oct 24–Nov 1 is now producing adults.

The week ahead

Each day's Bite Index, from this week's weather and the rain that is still hatching. Forecast days get less certain as the week goes on.

  1. Today
    86Severe86°/65°dry
  2. Mon
    94Severe83°/63°dry
  3. Tue
    94Severe84°/68°dry
  4. Wed
    94Severe84°/72°0.1 in
  5. Thu
    93Severe80°/73°dry
  6. Fri
    91Severe75°/63°0.1 in
  7. Sat
    63V·High67°/52°dry

Protect tonight

Treat the outdoors like a swarm: cover up and use a full-strength repellent.

  1. 25–30% DEET or 20% picaridin on every bit of exposed skin, plus permethrin-treated clothing for anything longer than a quick trip outside.
  2. Keep kids and pets in around dusk and dawn; schedule outdoor time for midday when it's hottest and driest.
  3. If your health department has an active West Nile advisory for your ZIP, follow it over anything on this page.
Which repellent, and how much: DEET vs picaridinBest natural repellents

Why Fort Myers's mosquitoes do what they do

Fort Myers sits on the Caloosahatchee between the Gulf and the Everglades' western edge, with mangroves, salt marsh and summer floodwater on every side. The Lee County Mosquito Control District is one of the largest programs anywhere, with its own airfield and fleet, because the salt-marsh broods off the mangroves would otherwise make the coast unlivable.

  • Mangroves and salt marsh: Estero Bay, Pine Island Sound and the Caloosahatchee shore produce salt-marsh Aedes broods on every spring tide.
  • Wet season: near-daily storms from June through September flood the interior.
  • Aedes aegypti: container breeders in Cape Coral's canals and lanais carry dengue when it is introduced.
  • Aerial control: the district treats by air; its notices say where and when.

A typical year in Lee County

What the Bite Index typically reads here each month, from Lee County's 30-year climate normals run through the same model as today's number. The month you're in is marked; the season map shows the same long-run picture for every county.

  1. JJanuary: 5
  2. FFebruary: 5
  3. MMarch: 30
  4. AApril: 60
  5. MMay: 79
  6. JJune: 86
  7. JJuly: 86
  8. AAugust: 86
  9. SSeptember: 86
  10. OOctober: 84
  11. NNovember: 64
  12. DDecember: 20

Local surveillance and West Nile virus

The Bite Index measures nuisance biting, not disease. Lee County's health department traps and tests mosquitoes through the season and publishes positive West Nile pools by ZIP code. When your ZIP has an active advisory, follow it regardless of today's number.

How the Bite Index is scored

The index is a model of conditions, not a mosquito count. Warmth and water set the size of the population, tonight's weather sets how much of it flies, and the season and local reports adjust the result. Every factor and today's value for it is listed here so you can check the number yourself. Warmth and Water are exactly the climate core of our county-level mosquito season map; the map shows that core on 30-year normals for every county, and “typical for this month” is the same model run on this county's normals, so the comparison is like for like.

WWater

Rain over the egg-to-adult window (0.8 in. between Oct 24 and Nov 1), expressed as a monthly rate on the same wetness curve the season map uses. At summer temperatures eggs become biting adults in about a week, so today's mosquitoes are last week's rain. Cool weather stretches the window; hot dry days shrink it. Irrigation, creeks and pools keep a 35% floor even in a drought.

Role scales
Today 85%

TWarmth

The trailing two-week average temperature on the season map's curve: nothing below 50°F, full speed at 78–88°F, a small penalty in extreme heat. Multiplied with Water, so a cool fortnight caps the index however wet it has been.

Role gates
Today 95%

ATonight

Whether the population that exists will actually fly and bite this evening: dusk temperature (65–85°F is ideal), wind (they stop flying around 10 mph), humidity, and rain around sunset. Scales the index between half and full.

Role 0.5–1×
Today 100%

GGround truth

A nudge from local trap counts and reports when we have them. For Fort Myers this is neutral today; the health department's surveillance is linked above and will feed this factor as we wire it in.

Role ±15%
Today neutral

SSeason gate

A multiplier from the calendar: fully open in the city's season months, half-open in the shoulder months, nearly closed in deep winter unless the week is warm. Below a 50°F weekly average the index is simply 0.

Role ×
Today 100%

index = 100 × S × [T × (0.35 + 0.65·W)] × (0.5 + 0.5·A) × (1 + 0.15·G)

Bands: Low 0–20 · Moderate 21–40 · High 41–60 · Very High 61–80 · Severe 81–100. Weather is from Open-Meteo (observations and the 7-day forecast), refreshed hourly. The lag and temperature thresholds follow published work on Culex and Aedes development (Rueda et al. 1990; Cornell NRCC degree-day emergence; JAMCA 2024 on rainfall two to four weeks before trap peaks).

Questions people ask about mosquitoes in Fort Myers

When is mosquito season in Fort Myers?
Year-round, peaking from June through October with the wet season. The driest weeks of the winter are the only lull, and salt-marsh broods can come on any spring tide.
Why does Lee County need so many aircraft?
Salt-marsh mosquitoes hatch by the billion when tides or storms flood the mangroves, and they fly up to 20 miles. The district's air fleet treats the marsh before adults emerge; without it, the coast would not be habitable in summer.
Is dengue a risk in Fort Myers?
It can be. Aedes aegypti is established, and Southwest Florida has recorded locally acquired dengue in recent years. The health department's advisories are authoritative; follow them over the index.
Where does this forecast's data come from?
Open-Meteo weather for downtown Fort Myers, scored by our documented model and compared with Lee County's season-map climatology. It does not include tide data, which drives salt-marsh broods.

Also covers Cape Coral, Bonita Springs, Estero, Lehigh Acres, Sanibel, Fort Myers Beach, Pine Island, Six Mile Cypress Slough: the forecast point is central Fort Myers, and conditions within about 30 miles track it closely. Weather fetched Nov 8, 5:28 PM local time.

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