Current Conditions

O'Fallon, Illinois

88°F31°C

Light Rain

Feels like95°F35°C

Wind

SE 5 mph8 km/h

Humidity

61%

Cloud Cover

93%

As of Wednesday, August 12, 2026 at 5:49 PM CDT

Today's Outlook

Day

Overcast and hot, with a high of 94°F34°C — feels like 102°F39°C. Light wind from the WSW around 5 mph8 km/h. 39% chance of light rain in the afternoon. Heat risk in the afternoon.

Night

Overcast, with a low around 82°F28°C. Light wind from the ESE around 5 mph8 km/h. 32% chance of light rain throughout the night.

7-Day Forecast

Condition	High (°F)	Low (°F)	Precip (mm)	Cloud Cover (%)	Wind (mph)
Light Rain	High 94°F34°CFeels 102°F39°C	Low 82°F28°CFeels 87°F30°C	Precip 0.07 in1.9 mm39%	Cloud 93%	Wind SSE 5 mph8 km/h	Wednesday: Overcast and hot, with a high of 94°F34°C — feels like 102°F39°C. Light wind from the WSW around 5 mph8 km/h. 39% chance of light rain in the afternoon. Heat risk in the afternoon. Wednesday Night: Overcast, with a low around 82°F28°C. Light wind from the ESE around 5 mph8 km/h. 32% chance of light rain throughout the night.
Drizzle	High 93°F34°CFeels 101°F38°C	Low 77°F25°C	Precip 0.02 in0.6 mm10%	Cloud 83%	Wind SE 5 mph8 km/h	Thursday: Overcast and hot, with a high of 93°F34°C and morning low of 77°F25°C — feels like 100°F38°C. Light wind from the S around 4 mph7 km/h. Heat risk in the afternoon. Thursday Night: Mostly cloudy, with a low around 77°F25°C. Breezy from the SE at 5 to 8 mph9 to 12 km/h. 10% chance of drizzle overnight.
Hot	High 96°F35°CFeels 105°F40°C	Low 79°F26°C	Precip 0.01 in0.3 mm5%	Cloud 75%	Wind SSE 5 mph8 km/h	Friday: Overcast and hot, with a high of 96°F35°C and morning low of 79°F26°C — feels like 104°F40°C. Light wind from the S around 4 mph7 km/h. Heat risk in the afternoon. Friday Night: Mostly cloudy, with a low around 80°F27°C. Breezy from the SSE at 6 to 7 mph10 to 12 km/h.
Drizzle	High 98°F37°CFeels 103°F39°C	Low 80°F27°C	Precip 0.02 in0.6 mm12%	Cloud 53%	Wind SSW 6 mph9 km/h	Saturday: Mostly cloudy and hot, with a high of 98°F37°C and morning low of 80°F27°C. Light wind from the SW around 5 mph9 km/h. 12% chance of drizzle in the morning. Heat risk in the afternoon. Saturday Night: Partly cloudy, with a low around 82°F28°C. Breezy from the S at 6 to 7 mph10 to 11 km/h.
Drizzle	High 101°F38°CFeels 105°F40°C	Low 81°F27°C	Precip 0.01 in0.3 mm13%	Cloud 38%	Wind W 7 mph11 km/h	Sunday: Partly cloudy and hot, with a high of 101°F38°C and morning low of 81°F27°C. Breezy from the W at 7 mph11 km/h. Heat risk in the afternoon. Sunday Night: Partly cloudy, with a low around 82°F28°C. Breezy from the WSW at 7 to 8 mph11 to 12 km/h. 13% chance of drizzle in the evening.
Showers	High 90°F32°CFeels 94°F34°C	Low 76°F24°C	Precip 0.06 in1.4 mm14%	Cloud 53%	Wind N 6 mph10 km/h	Monday: Mostly cloudy and hot, with a high of 90°F32°C and morning low of 76°F24°C. Light wind from the NNW around 6 mph10 km/h. 11% chance of drizzle in the morning. Humid. Monday Night: Mostly cloudy, with a low around 78°F26°C. Breezy from the N at 6 to 7 mph10 to 11 km/h. 14% chance of showers overnight.
Hot	High 92°F34°CFeels 95°F35°C	Low 72°F22°C	Precip 0.04 in0.9 mm8%	Cloud 33%	Wind E 4 mph7 km/h	Tuesday: Partly cloudy and hot, with a high of 92°F34°C and morning low of 72°F22°C. Light wind from the E around 3 mph6 km/h. Heat risk in the afternoon. Tuesday Night: Partly cloudy, with a low around 73°F23°C. Light wind from the E around 5 mph8 km/h.

15-Day Forecast

	Day	High	Low	Precip	Cloud Cover	Condition	Wind
	WednesdayAug 12	94°F34°C Feels 102°F39°C	82°F28°C Feels 87°F30°C	0.07 in1.9 mm· 39%	93%	Light Rain	SSE 5 mph8 km/h
DayOvercast and hot, with a high of 94°F34°C — feels like 102°F39°C. Light wind from the WSW around 5 mph8 km/h. 39% chance of light rain in the afternoon. Heat risk in the afternoon. NightOvercast, with a low around 82°F28°C. Light wind from the ESE around 5 mph8 km/h. 32% chance of light rain throughout the night.
	ThursdayAug 13	93°F34°C Feels 101°F38°C	77°F25°C	0.02 in0.6 mm· 10%	83%	Drizzle	SE 5 mph8 km/h
DayOvercast and hot, with a high of 93°F34°C and morning low of 77°F25°C — feels like 100°F38°C. Light wind from the S around 4 mph7 km/h. Heat risk in the afternoon. NightMostly cloudy, with a low around 77°F25°C. Breezy from the SE at 5 to 8 mph9 to 12 km/h. 10% chance of drizzle overnight.
	FridayAug 14	96°F35°C Feels 105°F40°C	79°F26°C	0.01 in0.3 mm· 5%	75%	Hot	SSE 5 mph8 km/h
DayOvercast and hot, with a high of 96°F35°C and morning low of 79°F26°C — feels like 104°F40°C. Light wind from the S around 4 mph7 km/h. Heat risk in the afternoon. NightMostly cloudy, with a low around 80°F27°C. Breezy from the SSE at 6 to 7 mph10 to 12 km/h.
	SaturdayAug 15	98°F37°C Feels 103°F39°C	80°F27°C	0.02 in0.6 mm· 12%	53%	Drizzle	SSW 6 mph9 km/h
DayMostly cloudy and hot, with a high of 98°F37°C and morning low of 80°F27°C. Light wind from the SW around 5 mph9 km/h. 12% chance of drizzle in the morning. Heat risk in the afternoon. NightPartly cloudy, with a low around 82°F28°C. Breezy from the S at 6 to 7 mph10 to 11 km/h.
	SundayAug 16	101°F38°C Feels 105°F40°C	81°F27°C	0.01 in0.3 mm· 13%	38%	Drizzle	W 7 mph11 km/h
DayPartly cloudy and hot, with a high of 101°F38°C and morning low of 81°F27°C. Breezy from the W at 7 mph11 km/h. Heat risk in the afternoon. NightPartly cloudy, with a low around 82°F28°C. Breezy from the WSW at 7 to 8 mph11 to 12 km/h. 13% chance of drizzle in the evening.
	MondayAug 17	90°F32°C Feels 94°F34°C	76°F24°C	0.06 in1.4 mm· 14%	53%	Showers	N 6 mph10 km/h
DayMostly cloudy and hot, with a high of 90°F32°C and morning low of 76°F24°C. Light wind from the NNW around 6 mph10 km/h. 11% chance of drizzle in the morning. Humid. NightMostly cloudy, with a low around 78°F26°C. Breezy from the N at 6 to 7 mph10 to 11 km/h. 14% chance of showers overnight.
	TuesdayAug 18	92°F34°C Feels 95°F35°C	72°F22°C	0.04 in0.9 mm· 8%	33%	Hot	E 4 mph7 km/h
DayPartly cloudy and hot, with a high of 92°F34°C and morning low of 72°F22°C. Light wind from the E around 3 mph6 km/h. Heat risk in the afternoon. NightPartly cloudy, with a low around 73°F23°C. Light wind from the E around 5 mph8 km/h.
	WednesdayAug 19	99°F37°C	76°F24°C	0.02 in0.5 mm· 8%	46%	Hot	S 7 mph11 km/h
DayPartly cloudy and hot, with a high of 99°F37°C and morning low of 76°F24°C. Breezy from the SSW at 7 to 8 mph11 to 12 km/h. Heat risk in the afternoon. NightPartly cloudy, with a low around 77°F25°C. Breezy from the SSE at 6 to 7 mph10 to 12 km/h.
	ThursdayAug 20	96°F35°C	76°F25°C	0.03 in0.8 mm· 8%	37%	Hot	W 7 mph11 km/h
DayPartly cloudy and hot, with a high of 96°F35°C and morning low of 76°F25°C. Light wind from the W around 6 mph10 km/h. Heat risk in the afternoon. NightPartly cloudy, with a low around 79°F26°C. Breezy from the SE at 7 to 8 mph11 to 12 km/h.
	FridayAug 21	95°F35°C	74°F23°C	0.06 in1.5 mm· 11%	33%	Drizzle	E 6 mph9 km/h
DayPartly cloudy and hot, with a high of 95°F35°C and morning low of 74°F23°C. Light wind from the WNW around 6 mph9 km/h. 11% chance of drizzle throughout the day. NightPartly cloudy, with a low around 76°F24°C. Light wind from the E around 6 mph9 km/h. 11% chance of drizzle before dawn.
	SaturdayAug 22	95°F35°C	73°F23°C	0.02 in0.5 mm· 6%	31%	Clear	NNE 6 mph9 km/h
DayPartly cloudy and hot, with a high of 95°F35°C and morning low of 73°F23°C. Light wind from the NNW around 6 mph9 km/h. NightPartly cloudy, with a low around 76°F24°C. Light wind from the ENE around 6 mph10 km/h.
	SundayAug 23	94°F34°C	72°F22°C	0.02 in0.6 mm· 10%	34%	Drizzle	NE 6 mph10 km/h
DayPartly cloudy and hot, with a high of 94°F34°C and morning low of 72°F22°C. Light wind from the N around 6 mph10 km/h. 10% chance of drizzle in the afternoon. NightPartly cloudy, with a low around 75°F24°C. Light wind from the ENE around 6 mph10 km/h.
	MondayAug 24	93°F34°C	71°F22°C	0.03 in0.8 mm· 10%	36%	Drizzle	ENE 6 mph10 km/h
DayPartly cloudy and hot, with a high of 93°F34°C and morning low of 71°F22°C. Light wind from the N around 6 mph9 km/h. NightPartly cloudy, with a low around 74°F23°C. Light wind from the ENE around 6 mph10 km/h. 10% chance of drizzle in the evening.
	TuesdayAug 25	92°F33°C	71°F22°C	0.04 in1 mm· 10%	34%	Drizzle	NNE 6 mph9 km/h
DayPartly cloudy and hot, with a high of 92°F33°C and morning low of 71°F22°C. Light wind from the N around 6 mph9 km/h. 10% chance of drizzle in the morning. NightPartly cloudy, with a low around 73°F23°C. Light wind from the NE around 6 mph9 km/h.
	WednesdayAug 26	90°F32°C	70°F21°C	0.04 in1 mm· 12%	40%	Drizzle	NE 6 mph9 km/h
DayPartly cloudy and hot, with a high of 90°F32°C and morning low of 70°F21°C. Light wind from the NNE around 6 mph9 km/h. 12% chance of drizzle throughout the day. NightPartly cloudy, with a low around 73°F23°C. Light wind from the ENE around 6 mph9 km/h.

Nearby Cities

Fairview Heights4 mi7 km Belleville6 mi10 km Collinsville7 mi11 km East Saint Louis13 mi21 km Granite City15 mi24 km Edwardsville15 mi25 km

About This Forecast

This forecast is powered by WeatherMesh, the world's most advanced and accurate weather model powered by AI. WeatherMesh is built on proprietary data from WindBorne's Global Sounding Balloon constellation — the world's largest fleet of autonomous, long-duration weather balloons — collecting observations across 100% of Earth, including over oceans and remote regions where no other data exists.

WeatherMesh consistently outperforms legacy models in independent benchmarks. View Benchmarks →

Access WeatherMesh forecasts programmatically via our API. API Documentation →

How to Access Weather Forecasts

Pattern	Example	Description
/weather/{country}/{city}/	/weather/united-states/san-francisco/	City forecast (canonical URL)
/weather/{city}/	/weather/tokyo/	Shorthand — redirects to most populous match
/weather/{country}/{region}/{city}/	/weather/united-states/california/san-francisco/	With region — redirects to canonical
/weather/nearby?lat={lat}&lon={lon}	/weather/nearby?lat=48.1&lon=11.5	Find nearest city by coordinates
/weather/{country}/	/weather/germany/	Country index — all cities by region

Country and city names use lowercase slugs with hyphens (e.g. united-states, san-francisco). Arbitrary city names are supported — if not in our database, we geocode the name and serve the forecast for that location.

For programmatic access, use theWindBorne Forecast APIwhich returns structured JSON for any coordinates worldwide.

Coordinates: 38.5923°N, 89.9112°W·Elevation: 167m·Timezone: America/Chicago·Population: 29,002