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Dallas Mosquito Forecast

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

Bite Index · Sunday, November 8

High

High mosquito activity in Dallas today and easing through the week. Cover up or use repellent after 6 pm.

Bites within a few minutes outdoors at dusk. Repellent or long sleeves pay off.

About normal for November in Dallas County.

  • Only 0.1 in. of rain Oct 19–Oct 30, so few new breeding sites; what's biting is coming from irrigation, pools and creeks.
  • Tonight: a cool 63°F evening, light wind — good flying weather for mosquitoes.
  • 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
    51High71°/58°dry
  2. Mon
    54High74°/54°dry
  3. Tue
    54High76°/60°dry
  4. Wed
    43High80°/64°dry
  5. Thu
    40Mod.69°/56°dry
  6. Fri
    32Mod.58°/48°dry
  7. Sat
    44High70°/50°dry

Protect tonight

Use repellent for any time outside after about 6 pm.

  1. 20% picaridin or 20–30% DEET for the evening; follow the label's reapplication window.
  2. Long sleeves and pants in light colors cut bites roughly in half on their own.
  3. Skip the yard work at dusk: the hour around sunset is the heaviest biting of the day.
Which repellent, and how much: DEET vs picaridinBest natural repellents

Why Dallas's mosquitoes do what they do

Dallas has the most closely watched mosquitoes in Texas: after the 2012 West Nile outbreak, Dallas County Health and Human Services built a weekly surveillance program that publishes positive pools by city and ZIP all season. The city's heavy clay soil and the Trinity River bottoms hold spring rain for weeks, then a hot dry summer concentrates both people and mosquitoes around irrigated yards and storm drains.

  • Blackland clay: rain puddles rather than draining, so May and June storms produce long-lived breeding sites.
  • Trinity River floodplain and White Rock Creek: the greenbelts that cool the city are also its mosquito nurseries.
  • Storm drains and catch basins: in a dry August the Culex that carry West Nile breed in the water that stands below street level.
  • Real winter: hard freezes end the season in late November, so the index goes to zero in a way it rarely does on the Gulf Coast.

A typical year in Dallas 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: 30
  4. AApril: 55
  5. MMay: 83
  6. JJune: 100
  7. JJuly: 95
  8. AAugust: 83
  9. SSeptember: 92
  10. OOctober: 75
  11. NNovember: 51
  12. DDecember: 0

Local surveillance and West Nile virus

The Bite Index measures nuisance biting, not disease. Dallas 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 19 and Oct 30). 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 67%

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 84%

GGround truth

A nudge from local trap counts and reports when we have them. For Dallas 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 100%

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 Dallas

When is mosquito season in Dallas?
April through October, with spring floodwater mosquitoes in May and June and the West Nile-carrying Culex peaking in the hot months of July through September. The first hard freeze, usually late November, ends it.
Why does Dallas have a West Nile problem?
Culex quinquefasciatus thrives in the polluted standing water of an urban summer: storm drains, gutters, neglected pools. The 2012 outbreak made Dallas County the most-studied West Nile setting in the country, and the weekly surveillance that followed is why positive pools are reported quickly here.
Is West Nile virus a risk in Dallas right now?
Check Dallas County's West Nile Watch, linked above: it lists positive pools by city and ZIP each week in season. When your area is listed, treat dusk and dawn as high-risk hours whatever the Bite Index says.
Where does this forecast's data come from?
Open-Meteo weather for central Dallas, scored by our documented model. It is a measure of nuisance-biting conditions, not a trap count, and it does not replace the county's surveillance.

Also covers Plano, Irving, Garland, Richardson, Mesquite, Highland Park, White Rock Lake, the Trinity River Greenbelt: the forecast point is central Dallas, and conditions within about 30 miles track it closely. Weather fetched Nov 8, 12:38 PM local time.

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