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Lafayette Mosquito Forecast

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

Bite Index · Sunday, November 8

Moderate

Moderate mosquito activity in Lafayette today and climbing toward very high by Nov 11: expect some bites at dusk.

Some bites at dusk and dawn, mostly near creeks, gardens and shade.

About normal for November in Lafayette Parish (typically around 31).

  • 0.5 in. of rain Oct 21–Oct 30 is now producing adults (cool weather slowed the hatch, so the window is longer than usual).
  • Tonight: a cool 57°F evening, light wind — average conditions for biting.
  • A two-week average of 69°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
    29Mod.69°/49°dry
  2. Mon
    46High74°/51°dry
  3. Tue
    54High78°/53°dry
  4. Wed
    64V·High79°/63°dry
  5. Thu
    46High74°/52°dry
  6. Fri
    29Mod.59°/43°dry
  7. Sat
    27Mod.64°/39°dry

Protect tonight

Worth repellent if you'll be outside at dusk or dawn.

  1. A botanical or 10% picaridin lotion covers a patio evening; reapply after about two hours.
  2. A fan on the patio does real work: mosquitoes are weak fliers and avoid moving air.
Which repellent, and how much: DEET vs picaridinBest natural repellents

Why Lafayette's mosquitoes do what they do

Lafayette is the heart of Acadiana, a flat, wet parish of bayous, rice fields and crawfish ponds, and mosquitoes are a fact of life in every month. Lafayette Consolidated Government's Mosquito Control program sprays by truck and air across the parish and added aerial treatment in recent years as West Nile pressure grew.

  • Bayous and the Vermilion River: permanent habitat threading the city.
  • Rice and crawfish ponds: flooded fields around the parish are vast floodwater and Culex habitat.
  • Sixty inches of rain: no dry season to speak of.
  • Spring and fall peaks, midsummer lull: like New Orleans, May–June and September–October are the worst.

A typical year in Lafayette Parish

What the Bite Index typically reads here each month, from Lafayette Parish'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: 1
  2. FFebruary: 2
  3. MMarch: 17
  4. AApril: 50
  5. MMay: 72
  6. JJune: 86
  7. JJuly: 86
  8. AAugust: 86
  9. SSeptember: 86
  10. OOctober: 65
  11. NNovember: 31
  12. DDecember: 6

Local surveillance and West Nile virus

The Bite Index measures nuisance biting, not disease. Lafayette Parish'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 (0.5 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 38%

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 66%

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 48%

GGround truth

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

When is mosquito season in Lafayette?
Essentially year-round, peaking from May through June and again from September through October. Only a January cold snap quiets them.
Why are Acadiana's mosquitoes so bad?
Flat ground, sixty inches of rain, and flooded rice and crawfish fields on every side: the parish is surrounded by ideal breeding habitat, and the bayous keep it wet between rains.
Is West Nile virus a risk in Lafayette?
Yes. Lafayette Parish records positive pools most summers and the state reports human cases in Acadiana most years. LCG's spray notices and the state report are authoritative; follow them over the index.
Where does this forecast's data come from?
Open-Meteo weather for central Lafayette, scored by our documented model and compared with the parish's climate normals. Not a trap count.

Also covers Youngsville, Broussard, Scott, Carencro, Breaux Bridge, New Iberia, the Vermilion River, Acadiana Park: the forecast point is central Lafayette, and conditions within about 30 miles track it closely. Weather fetched Nov 8, 4:28 PM local time.

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