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Birmingham Mosquito Forecast

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

Bite Index · Sunday, November 8

Low

Mosquito activity in Birmingham is low today.

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

Quieter than a typical November in Jefferson County (usually around 39).

  • Tonight: a cool 51°F evening, light wind — poor flying weather, so fewer bites than the population alone would suggest.
  • Only 0.1 in. of rain Oct 17–Oct 29, so few new breeding sites; what's biting is coming from irrigation, pools and creeks.
  • At a two-week average of 63°F, larvae develop slowly and numbers are easing.

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
    16Low67°/38°dry
  2. Mon
    19Low72°/39°dry
  3. Tue
    22Mod.71°/48°dry
  4. Wed
    29Mod.73°/56°dry
  5. Thu
    14Low61°/46°dry
  6. Fri
    13Low47°/37°0.1 in
  7. Sat
    12Low54°/34°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 Birmingham's mosquitoes do what they do

Birmingham sits in the Jones Valley between Red Mountain and the ridges to the north, with Village and Shades Creeks running through the city and some of the most humid summers in the South. The Jefferson County Department of Health handles mosquito complaints and spraying, and the county records West Nile cases most years.

  • Creeks and ridges: Village Creek and Shades Creek pool in the valley bottoms after storms.
  • Deep South humidity: dusk humidity stays high from May through September.
  • Tree canopy: shade and leaf-filled containers favor the daytime-biting Asian tiger mosquito.
  • Real winter: frosts from November end the season.

A typical year in Jefferson County

The long-run mosquito index by month from our season map (NOAA climate normals plus effort-corrected sightings). Today's Bite Index is the live version of this; the month you're in is marked.

  1. JJanuary: 0
  2. FFebruary: 0
  3. MMarch: 21
  4. AApril: 47
  5. MMay: 78
  6. JJune: 98
  7. JJuly: 92
  8. AAugust: 89
  9. SSeptember: 89
  10. OOctober: 68
  11. NNovember: 39
  12. DDecember: 0

Local surveillance and West Nile virus

The Bite Index measures nuisance biting, not disease. Jefferson 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. Four weather factors are combined on a 0–100 scale, then scaled by the season. Every factor and today's value for it is listed here so you can check the number yourself. It uses the same temperature curve and rain logic as our county-level mosquito season map, which has been validated against effort-corrected sighting data across 41 states.

BBreeding pressure

Rain 7–14 days ago (0.1 in. between Oct 17 and Oct 29). Eggs need water to hatch, and at summer temperatures the egg-to-biting-adult cycle takes about a week, so today's mosquitoes are last week's rain. Cool weather stretches the window; hot dry days shrink it as shallow water evaporates.

Weight 40%
Today 0%

DDevelopment

The trailing two-week average temperature, on the same curve as our national season map: nothing below 50°F, full speed at 78–88°F, a small penalty in extreme heat.

Weight 25%
Today 46%

ATonight's activity

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.

Weight 25%
Today 8%

GGround truth

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

Weight 10%
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.

Weight ×
Today 60%

index = 100 × S × (0.40 × (0.2 + 0.8·B) + 0.25 × D + 0.25 × A + 0.10 × (0.5 + 0.5·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 Birmingham

When is mosquito season in Birmingham?
April through October, peaking from June through September. The first frost, usually November, ends it.
Why do I get bitten in the daytime in Birmingham?
The Asian tiger mosquito, which breeds in small shaded containers, is a daytime biter and the dominant nuisance species in Birmingham's leafy neighborhoods. Emptying saucers and cleaning gutters matters more than spraying.
Is West Nile virus a risk in Birmingham?
Yes. Jefferson County records West Nile cases most years. The Department of Health's advisories are authoritative; follow them over the index.
Where does this forecast's data come from?
Open-Meteo weather for downtown Birmingham, scored by our documented model and compared with Jefferson County's season-map climatology. Not a trap count.

Also covers Hoover, Vestavia Hills, Mountain Brook, Homewood, Trussville, Bessemer, Railroad Park, Oak Mountain: the forecast point is central Birmingham, and conditions within about 30 miles track it closely. Weather fetched Nov 8, 12:38 PM local time.

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