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Affton, Missouri Weather

Cicadas claim the scorching afternoon. Day 15 of summer. Read this microseason across nine climate regions →

Affton weather forecast — hour by hour, 7-day outlook, NOAA radar

Affton, MO
Saturday, July 4 at 10:25 PM
71
°
Overcast
Feels like
76°
Humidity
88%
Wind
5 mph
Sunrise
12:42 AM
Sunset
3:29 PM
Affton, MO
Hour by hour · 24h
24-Hour ForecastAffton, MO: 24-hour forecast. Temperatures range from 68 to 87 degrees Fahrenheit with a 30% chance of precipitation at 5 PM.
L 68°H 87°
Affton, MO
7-day forecast
  1. Today
    Jul 4
    Showers
    53%
    0.28″
    87°71°—
  2. Sunday
    Jul 5
    Heavy Rain
    30%
    1.4″
    87°68°0°
  3. Monday
    Jul 6
    Overcast
    13%
    —
    85°70°-2°
  4. Tuesday
    Jul 7
    Clear
    13%
    —
    90°71°+5°
  5. Wednesday
    Jul 8
    Overcast
    —
    —
    98°71°+8°
  6. Thursday
    Jul 9
    Overcast
    39%
    —
    97°78°-1°
  7. Friday
    Jul 10
    Light Drizzle
    39%
    0.02″
    93°72°-4°
Affton, MO
Next 24 hours · Mild now
HOT 90°64°77°90°6p12a6a12pnow 72°high 87°low 68°PRECIP %
Affton, MO
Anemometer · 24h winds · from true
NESW
From · True
WSW
240° · veering 21°
Direction
WSW
240°
Sustained
5
mph
Gust
13
mph
Peak 24h
22
avg 5
Beaufort · 2 · LIGHT BRZ
0
CALM
<1
1
LIGHT AIR
1–3
2
LIGHT BRZ
4–7
3
GENTLE BRZ
8–12
4
MOD BRZ
13–18
5
FRESH BRZ
19–24
6
STRONG BRZ
25–31
7
NEAR GALE
32–38
24h · sust vs gust · mph
avg 5 · pk 22 @ 5:00p
01020MPHB1B2B3B4B5-21h-18h-15h-12h-9h-6h-3h-24hNOWpk 183SUSTGUST
−24h−18h−12h−6hnow
Light breeze veering 21° from the wsw.
Affton, MO
Barometer · 24h pressure · mb
STORMRAINCHANGEFAIRDRY9901000101010201030
Pressure · mb
993.5
+1.1 mb in 3h · rising · 29.34 inHg
Now
993.5
mb
3h
+1.1
mb
12h
-2.4
mb
24h
-2.4
mb
Regime · STORM
STORM
RAIN
CHANGE
FAIR
DRY
24h · Pressure · mb
range 992–996
9859909951000STORM|RAIN10051010RAIN|CHG1015CHG|FAIR10201025FAIR|DRY1030-21h-18h-15h-12h-9h-6h-3h-24hNOW996.3992.4993.5
−24h−18h−12h−6hnow
The low is filling — pressure climbing out of storm territory.
Affton, MO
Air quality
52
AQI
Moderate
→+1 in 6h

AQI 52 (Moderate), driven by PM2.5. AQI flat over the last 6 hours (within ±3 points). PM2.5 at 16.6 µg/m³ (AQI 65) with a 0.89 fine-to-coarse ratio and 5 mph wind — combustion smoke trapped in calm air, not road dust.

OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion.

PM 2.5DRIVERModerate
16.6μg/m³
PM 10Good
19μg/m³
NO₂Good
16μg/m³
OzoneGood
59μg/m³
UV IndexLow
0.0

What's driving it

PM × Wind × Precip

PM2.5 at 16.6 µg/m³ (AQI 65) with a 0.89 fine-to-coarse ratio and 5 mph wind — combustion smoke trapped in calm air, not road dust.

PM2.5/PM10
0.89
Wind
light
Recent rain
0h in last 6h
Pattern
stagnant smoke

Trends

Seven days of AQI and PM2.5.

Hourly air-quality data from the Copernicus Atmosphere Monitoring Service, charted across the past and next several days. Dashed lines mark the AQI breakpoints at 50 (Good → Moderate) and 100 (Moderate → Unhealthy for Sensitive Groups).

7-DAY AQI TREND50100SUNMONTUEWEDTHUFRISATSUN7-DAY PM2.5 TREND · μg/m³320
Affton, MO
Sky cover · visibility · 24h
Cloud cover
90%
OVERCAST
100%0%−24h−18h−12h−6hnow
Visibility
28.9mi
UNLIMITED
47 mi0 mi−24h−18h−12h−6hnow
Earth · GOES-19 ABI
Full Disk · Visible · GeoColor
GOES-19 full disk Visible · GeoColor
True-color daytime, blue/IR sandwich at night
03:25 UTC · Affton, MO · NOAA NESDIS / STAR · up to 10848 px
Continental US · GOES-19 ABI
CONUS Sector · Visible · GeoColor
GOES-19 CONUS Visible · GeoColor
Daytime true-color, blue-light/IR sandwich at night
03:25 UTC · Affton, MO · NOAA NESDIS / STAR · 5-min cadence · up to 10000 px
Affton, MO
Satellite · infrared · animated
Affton, MO
Loading IR frames…
IR · cloud-top temp© RainViewer · Carto
Affton, MO
Almanac · Saturday, July 4
If the first of July be rainy weather, 'twill rain more or less for four weeks together.
Civil dawn
5:11 AM
Sunrise
12:42 AM
Daylight
14h 47m
Sunset
3:29 PM
Civil dusk
9:01 PM
Planting note
Harvest early potatoes. Begin drying onions on the surface.
Affton, MO
The moon
Waning Gibbous
76% illuminated
Moonrise
11:18 PM
Moonset
11:14 AM
In sign
♓︎ Pisces
Affton, MO
Microseason
Jul 1–5

Cicadas claim the scorching afternoon

plant
Jan 151% of the yearDec 31

Read this microseason across nine climate regions →

Affton at a glance

  • Today vs. normal: 71°F — typical for the season
  • Last frost: April 7 (climatological average for this latitude)
  • Microseason: Jul 1–5
  • Planting window: Harvest early potatoes. Begin drying onions on the surface.

16-Day Forecast — Affton

  1. Sat87°71°53%
  2. Sun87°68°30%
  3. Mon85°70°13%
  4. Tue90°71°13%
  5. Wed98°71°7%
  6. Thu97°78°39%
  7. Fri93°72°39%
  8. Sat86°74°24%
  9. Sun86°69°8%
  10. Mon88°65°4%
  11. Tue95°69°2%
  12. Wed98°75°6%
  13. Thu102°71°11%
  14. Fri104°79°20%
  15. Sat102°82°16%
  16. Sun103°81°24%

Forecast data from Open-Meteo (CC BY 4.0).

Right now in the garden

Peak growing season

As of July 5, the growing season is at its peak — frost is months away. Continue succession-planting beans and summer squash. Start fall brassicas (broccoli, cabbage, kale) from seed indoors for transplanting in late summer.

SPC Convective Outlook

Storm Prediction Center — Affton

SPC has placed Affton in the Marginal Risk category for severe thunderstorms today.

  • TODAYMRGLMarginal Risk
  • TOMORROWTSTMGeneral Thunderstorms
  • DAY 3TSTMGeneral Thunderstorms

Isolated severe storms possible. Limited threat for hail or damaging wind.

Source: NOAA / NWS Storm Prediction Center categorical convective outlook. Outlooks are re-issued multiple times per day; this page reflects the most recent SPC polygons covering the city’s coordinates.

January 1–5: Frost quiets the live oaks.January 6–10: Still water thickens with ice.January 11–15: Springs begin to move beneath ice.January 16–20: Cardinal dawn calls grow bolder.January 21–25: Late January thaw pulses.January 26–31: Last freeze locks the land.February 1–5: February's lengthening light.February 6–10: Warming winds thaw the margin.February 11–15: Magnolia blooms break the gray.February 16–20: Mockingbirds resume the dawn chorus.February 21–25: Rain replaces the last snow.February 26–28: Mist clings to greening valleys.March 1–5: The green pulse awakens.March 6–10: Hibernators emerge to call.March 11–15: Dogwood and redbud ignite.March 16–20: Swallowtails emerge from winter silk.March 21–25: Light crowns the dogwood canopy.March 26–31: Redbud cascades over the thaw.April 1–5: Thunder announces the wet season.April 6–10: Barn swallows carve the warming sky.April 11–15: Magnolia blooms and falls in a breath.April 16–20: First rainbows arch over thunderheads.April 21–25: Reeds push through marsh water.April 26–30: Frost retreats; seedlings rise free.May 1–5: Warblers flood the canopy in waves.May 6–10: Tulip poplar lights the forest crown.May 11–15: Shad pulse upstream through rapids.May 16–20: Roses open on the Piedmont edge.May 21–25: Fireflies scout the humid dusk.May 26–31: Frog choruses rise from every wetland.June 1–5: Fireflies pulse through the magnolias.June 6–10: Kudzu climbs deeper into green.June 11–15: Sun climbs to its northern throne.June 16–20: Heat settles and the rain begins.June 21–25: The longest day turns toward shadow.June 26–30: Fireflies drift through Spanish moss.July 1–5: Cicadas claim the scorching afternoon.July 6–10: Thunderheads boil and break at dusk.July 11–15: Thunder builds each drowsy afternoon.July 16–20: Cicadas claim the long noon.July 21–25: Dog days drape the earth in haze.July 26–31: Katydids begin their rasping chorus.August 1–5: Dusk arrives one minute earlier each night.August 6–10: Meteorological summer's turning page.August 11–15: Cool winds gather at the margins.August 16–20: Dog-day cicadas rise.August 21–25: Heat breaks in creek beds.August 26–31: Monarchs gather strength.September 1–5: Harvests begin in earnest.September 6–10: Dew beads on resurrection fern.September 11–15: Raptors trail the thermals.September 16–20: Day and dark find balance.September 21–25: Thunder quiets the land.September 26–30: Insects retreat below.October 1–5: Swamp waters recede.October 6–10: Maples ignite the ridge.October 11–15: Asters crown the meadows.October 16–20: Crickets sing at dusk.October 21–25: Frost paints the garden.October 26–31: Light rains whisper down.November 1–5: Sweetgum Turns Crimson.November 6–10: Camellia Blooms Break Through.November 11–15: Earth Stiffens Underfoot.November 16–20: Bare Limbs Hold the Light.November 21–25: First Frost Grips the High Ground.November 26–30: North Wind Strips the Last Leaves.December 1–5: Darkness Falls Before Dinner.December 6–10: Winter Locks the Land.December 11–15: Wildlife Retreats to Shelter.December 16–20: Ice Edges Deepen Inward.December 21–25: The Sun Begins its Return.December 26–31: The Year Turns in Silence.🌱February 14 — First skunk-cabbage spathes thaw their way up☀️March 20 — Spring equinox — day and night balance🌸April 5 — Cherry blossoms peak in the parks🐦May 10 — Warbler migration peaks along the coast✨May 25 — First fireflies scout the meadows at dusk🌞June 21 — Summer solstice — longest day🦗July 25 — Peak cicada chorus in the afternoons🌊August 18 — Warmest sea-surface temperatures of the year🍂September 22 — Autumn equinox — the slow turn❄️October 25 — First widespread frost in the suburbs🍁November 10 — Peak leaf color across the Hudson Valley🌙December 21 — Winter solstice — longest night

Microseason · July 1–5

Cicadas claim the scorching afternoon

Dog-day cicadas emerge in waves, their rasp dominating every sunny hour; heat peaks above 90 degrees daily.

Day 186 of 365 · Wedge 37 of 72

The solar year drawn as a wheel of 72 five-day windows. Each wedge is one microseason; the four colored arcs mark winter, spring, summer, and autumn; the small icons sit at notable phenological events. The crimson pointer creeps clockwise as the year turns.

Planting calendar

MonthPlantHarvest
January——
February——
March——
Aprillettuce, peas, spinach, radishes—
Maylettuce, peas, spinach, radishes, tomatoes, peppers, beans, squashlettuce, peas, radishes
Junetomatoes, peppers, beans, squashlettuce, peas, radishes
Julytomatoes, peppers, beans, squashtomatoes, beans, summer squash
August—tomatoes, beans, summer squash
Septemberfall brassicas, garlic (overwinter), carrotstomatoes, beans, summer squash
Octoberfall brassicas, garlic (overwinter), carrotswinter squash, tomatoes (last)
November——
December——

A year in weather

Affton peaks at about 81°F in July and bottoms near 33°F in January; May brings the heaviest rain (4.9 inches) and February the least (2.3 inches).

MonthMean tempPrecipRainy days
January33°2.7″9
February37°2.3″8
March47°3.6″12
April58°4.8″16
May68°4.9″16
June77°4.7″16
July81°4.2″14
August79°3.8″13
September72°3.4″11
October60°3.2″11
November48°3.7″12
December37°2.6″9

Regional context

In Affton, NOAA NCEI 1991-2020 normals put January near 33°F and July near 81°F — a 48°F seasonal arc — with about 43.9 inches of precipitation over 147 rainy or snowy days.

Summer convection drives Affton's precipitation: May logs 4.9 inches on 16.0 rainy days, against February's 2.3 inches on 8.0 — warm-season storms carry Affton's moisture. It is a warm-season-wet pattern Affton shares with places like Lakeshire, MO, Wilbur Park, MO and St. George, MO.

Affton reaches its last hard frost near mid-April; that is the cue for peas, lettuce, spinach, and radishes. Tomatoes and peppers do best set out two weeks later in Affton, once nights clear the mid-40s°F. By mid-November, frost is back in Affton — protect or harvest anything tender. Affton's low ground holds frost later into spring than Affton's benches, which run 3-5 days ahead.

Similar climates: Lakeshire, MO, Wilbur Park, MO, St. George, MO, Marlborough, MO, Grantwood Village, MO.

Frequently asked

When does it freeze in Affton?
Frost typically leaves Affton by mid-April and returns to Affton near mid-November.
What is the rainy season in Affton?
May is the wettest month in Affton, about 4.9 inches on average; the year totals roughly 44 inches.
What is the warmest month in Affton?
July is Affton's warmest month, averaging about 81°F.
What is the coldest month in Affton?
Affton bottoms out in January, with a mean near 33°F.
When can I start a vegetable garden in Affton?
Time tomatoes in Affton for two weeks after mid-April; peas and greens start at Affton's frost line.
How many rainy days does Affton get?
Affton records around 147 days of measurable precipitation annually.
What hardiness zone is Affton?
Affton sits in the USDA zone set by January lows near 33°F; the USDA ZIP tool gives the band.
What is the 10-day forecast for Affton?
Affton's extended outlook — daily high and low temperatures and precipitation chances for each upcoming day — is in the daily forecast above.
Will it rain this week in Affton?
See this week's day-by-day rain chances for Affton in the daily forecast above, and the next 24 hours in the hourly chart.
What is the weather like right now in Affton?
Current conditions for Affton and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
How often is the Affton forecast updated?
The Affton forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
When are sunrise and sunset in Affton?
Today's sunrise and sunset times for Affton are in the Almanac section above, along with civil dawn, civil dusk, and day length. Day length is longest near the summer solstice and shortest near the winter solstice.
How accurate is the weather forecast for Affton?
The next few days in Affton's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.

Climate

Affton, Missouri has a humid subtropical climate: January averages roughly 33°F, July about 81°F, 48°F between them.

Affton sees close to 44 inches of precipitation annually, falling across some 147 wet days.

Latitude 38.5°N gives Affton its 48°F swing, and with it the rhythm of Affton's growing season.

All cities in Missouri →

St. Louis, MO weather →

ZIP codes in Affton

  • 63123

Climate normals from the Open-Meteo Climate API. Köppen approximation from NOAA NCEI U.S. Climate Regions. See methodology for data sources, editorial rules, and corrections. Maintainer: Brian Tighe.