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Mobile Mosquito Forecast

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

Bite Index · Sunday, November 8

Low

Mosquito activity in Mobile is low today.

Few mosquitoes. You may see one or two at dusk near water.

About normal for November in Mobile County (typically around 28).

  • Only 0.0 in. of rain Oct 21–Oct 30, so few new breeding sites; what's biting is coming from irrigation, pools and creeks.
  • Tonight: a cool 58°F evening, light wind — average conditions for biting.
  • A two-week average of 68°F keeps populations growing, just more slowly than midsummer.

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
    17Low73°/43°dry
  2. Mon
    15Low75°/47°dry
  3. Tue
    19Low80°/49°dry
  4. Wed
    22Mod.81°/64°dry
  5. Thu
    16Low75°/51°dry
  6. Fri
    10Low59°/40°dry
  7. Sat
    9Low63°/36°dry

Protect tonight

You can probably skip repellent tonight.

  1. If you're near a creek, pond or heavy shade at dusk, a light application on ankles and arms is plenty.
  2. Good night to tip out any containers holding water; what you empty now won't hatch next week.
Which repellent, and how much: DEET vs picaridinBest natural repellents

Why Mobile's mosquitoes do what they do

Mobile is the rainiest major city in the country, a bay-side port surrounded by the Mobile-Tensaw Delta's swamps and marshes, and mosquitoes fly in every month. The Mobile County Health Department's Vector Services program sprays by truck and air from May through fall, traps across the county, and tests sentinel chickens that turned positive for West Nile and St. Louis encephalitis in 2026.

  • The Delta: the Mobile-Tensaw Delta is the second-largest river delta in the country and permanent habitat for floodwater and swamp species.
  • Sixty-five inches of rain: no dry season; breeding water is always present.
  • Salt marsh: the bay shore and Dauphin Island produce salt-marsh Aedes broods on spring tides.
  • West Nile and SLE: sentinel chickens and traps test positive most summers; human cases occur most years.

A typical year in Mobile County

What the Bite Index typically reads here each month, from Mobile 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: 0
  2. FFebruary: 1
  3. MMarch: 12
  4. AApril: 44
  5. MMay: 65
  6. JJune: 85
  7. JJuly: 86
  8. AAugust: 86
  9. SSeptember: 86
  10. OOctober: 62
  11. NNovember: 28
  12. DDecember: 4

Local surveillance and West Nile virus

The Bite Index measures nuisance biting, not disease. Mobile 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 (0.0 in. between Oct 21 and Oct 30), 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 0%

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 64%

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 56%

GGround truth

A nudge from local trap counts and reports when we have them. For Mobile 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 Mobile

When is mosquito season in Mobile?
Essentially year-round, peaking from May through October. MCHD's spraying season runs May to fall; a January cold snap is the only real lull.
Why are the mosquitoes so bad near the Causeway and the Delta?
The Delta's swamps and marshes are permanent breeding habitat, and salt-marsh species come off the bay shore on spring tides. Those broods fly miles into town.
Is West Nile virus a risk in Mobile?
Yes. Mobile County confirmed human cases in 2025 and 2026 and its sentinel chickens test positive most summers. MCHD's announcements are authoritative; follow them over the index.
Where does this forecast's data come from?
Open-Meteo weather for downtown Mobile, scored by our documented model and compared with Mobile County's season-map climatology. It does not include tide data, which drives salt-marsh broods.

Also covers Daphne, Fairhope, Spanish Fort, Saraland, Tillmans Corner, Dauphin Island, Bellingrath Gardens, the Causeway: the forecast point is central Mobile, and conditions within about 30 miles track it closely. Weather fetched Nov 8, 4:28 PM local time.

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