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Memphis Mosquito Forecast

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

Bite Index · Sunday, November 8

Low

Mosquito activity in Memphis is low today and climbing toward high by Nov 11.

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

About normal for November in Shelby County.

  • Tonight: a cool 49°F evening, light wind — poor flying weather, so fewer bites than the population alone would suggest.
  • Only 0.4 in. of rain Oct 16–Oct 29, so few new breeding sites; what's biting is coming from irrigation, pools and creeks.
  • At a two-week average of 62°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
    17Low62°/37°dry
  2. Mon
    31Mod.68°/39°dry
  3. Tue
    42High67°/45°dry
  4. Wed
    47High74°/58°0.2 in
  5. Thu
    32Mod.58°/45°dry
  6. Fri
    31Mod.49°/39°0.1 in
  7. Sat
    30Mod.54°/38°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 Memphis's mosquitoes do what they do

Memphis sits on the bluffs above the Mississippi with the Wolf and Loosahatchie Rivers and Nonconnah Creek running through it, and its summers are long, hot and humid. Shelby County's Vector Control program traps across the county, publishes a weekly spray schedule, and announces West Nile detections by ZIP code; in 2025 the county saw nine West Nile hospitalizations.

  • River bottoms: the Wolf River and Nonconnah Creek floodplains hold water for weeks after spring rain.
  • Humid summers: dusk humidity stays high from June through September, ideal flight conditions.
  • Culex and West Nile: Shelby County reports positive pools across many ZIPs most summers; the county sprays by neighborhood in response.
  • Hard freeze: the season ends in November and the index goes to zero through winter.

A typical year in Shelby 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: 15
  4. AApril: 38
  5. MMay: 64
  6. JJune: 88
  7. JJuly: 90
  8. AAugust: 95
  9. SSeptember: 91
  10. OOctober: 60
  11. NNovember: 24
  12. DDecember: 0

Local surveillance and West Nile virus

The Bite Index measures nuisance biting, not disease. Shelby 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 (0.4 in. between Oct 16 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 15%

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 42%

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 0%

GGround truth

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

When is mosquito season in Memphis?
May through October, peaking from June through September. Shelby County's spraying runs through that window; the first hard freeze, usually November, ends it.
Why are mosquitoes so bad near the Wolf River and Shelby Farms?
Floodplain pools left by spring rain are floodwater-mosquito habitat, and the shaded greenways hold humidity at dusk. Those areas run well above the citywide index.
Is West Nile virus a risk in Memphis?
Yes. Shelby County detects West Nile in mosquito pools across many ZIP codes most summers and had nine hospitalizations in 2025. The Health Department's ZIP-level alerts are authoritative; follow them over the index.
Where does this forecast's data come from?
Open-Meteo weather for downtown Memphis, scored by our documented model and compared with Shelby County's season-map climatology. A model of conditions, not a trap count.

Also covers Germantown, Collierville, Bartlett, Cordova, Southaven, West Memphis, Shelby Farms, Overton Park: the forecast point is central Memphis, and conditions within about 30 miles track it closely. Weather fetched Nov 8, 12:38 PM local time.

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