Observed 1:25 PM CDT at KCPS

O'Fallon, IL weather

Sunny and 75°24°.

Forecasts agree

Now 75°24°

Sunny

Wind: 6 mph10 km/h; From the southeast. Up to 6 mph10 km/h through 1 AM
Dew point: 46°8°; Comfortable
UV index: 4Moderate; Moderate until 4 PM
Air quality: 63Moderate; Main pollutant: PM2.5 (fine particles)
Pressure: 30.25 inHg1024 hPa; Falling · −0.07 inHg−2.4 hPa in 3 h

No precipitation expected in the next 2 hours.

From forecast models

Next 48 hours

Good hours for

High 76°24° today at 2 PM
Below 60°16° tonight after 9 PM
Low 47°8° tomorrow at 7 AM
Above 60°16° tomorrow by 10 AM

This afternoonNear 75°24° · Clear
TonightDown to 48°9° by 5 AM · Clear
Tomorrow morningUp to 66°19° by 11 AM · Mostly cloudy
Tomorrow afternoonUp to 76°24° by 4 PM · Mostly cloudy
Tomorrow nightDown to 50°10° by 4 AM · Partly cloudy
Sunday morningUp to 68°20° by 11 AM · Partly cloudy

Hourly forecast, next 48 hours, in the place's local time
Hour	Conditions	Temperature	Feels like	Precipitation	Wind	Humidity	Cloud cover	UV index
Fri 1p	Sunny	74°23° (likely 71°22° to 74°23°)	74°23°	0%	6 mph10 km/h from SE, gusts 10 mph16 km/h	40%	0%	4
Fri 2p	Sunny	76°24° (likely 72°22° to 76°24°)	76°24°	0%	6 mph10 km/h from SE, gusts 10 mph15 km/h	36%	0%	4
Fri 3p	Sunny	76°24° (likely 73°23° to 76°24°)	76°24°	0%	6 mph10 km/h from SE, gusts 9 mph14 km/h	36%	0%	3
Fri 4p	Sunny	76°24° (likely 72°22° to 76°24°)	76°24°	0%	5 mph8 km/h from SE, gusts 9 mph14 km/h	34%	0%	2
Fri 5p	Sunny	75°24° (likely 70°21° to 75°24°)	75°24°	0%	6 mph10 km/h from SE, gusts 10 mph16 km/h	36%	0%	1
Fri 6p	Clear	71°22° (likely 66°19° to 71°22°)	71°22°	0%	5 mph8 km/h from SE, gusts 8 mph13 km/h	41%	0%	0
Fri 7p	Clear	66°19° (likely 63°17° to 66°19°)	66°19°	0%	5 mph8 km/h from SE, gusts 9 mph14 km/h	50%	0%	0
Fri 8p	Clear	60°16° (likely 60°16° to 62°17°)	60°16°	0%	5 mph8 km/h from SE, gusts 10 mph15 km/h	64%	0%	0
Fri 9p	Clear	58°14° (likely 57°14° to 60°16°)	58°14°	0%	5 mph8 km/h from SE, gusts 10 mph16 km/h	72%	0%	0
Fri 10p	Clear	57°14° (likely 56°13° to 59°15°)	57°14°	0%	5 mph8 km/h from SE, gusts 11 mph18 km/h	75%	1%	0
Fri 11p	Mostly clear	55°13° (likely 54°12° to 58°14°)	55°13°	0%	3 mph5 km/h from SE, gusts 11 mph17 km/h	77%	14%	0
Sat 12a	Clear	54°12° (likely 53°12° to 57°14°)	54°12°	0%	3 mph5 km/h from SE, gusts 10 mph16 km/h	80%	31%	0
Sat 1a	Clear	53°12° (likely 52°11° to 56°13°)	53°12°	0%	2 mph3 km/h from SE, gusts 9 mph15 km/h	80%	39%	0
Sat 2a	Clear	51°11° (likely 51°11° to 54°12°)	51°11°	0%	2 mph3 km/h from SE, gusts 9 mph14 km/h	86%	34%	0
Sat 3a	Partly cloudy	50°10° (likely 50°10° to 53°12°)	50°10°	0%	2 mph3 km/h from SE, gusts 9 mph14 km/h	89%	33%	0
Sat 4a	Cloudy	49°9° (likely 49°9° to 52°11°)	49°9°	0%	2 mph3 km/h from SE, gusts 7 mph12 km/h	93%	71%	0
Sat 5a	Mostly clear	48°9° (likely 48°9° to 51°11°)	48°9°	0%	2 mph3 km/h from SE, gusts 7 mph11 km/h	96%	68%	0
Sat 6a	Mostly clear	48°9° (likely 47°8° to 50°10°)	48°9°	0%	2 mph3 km/h from SE, gusts 5 mph9 km/h	96%	46%	0
Sat 7a	Mostly sunny	47°8° (likely 46°8° to 49°9°)	47°8°	0%	2 mph3 km/h from SE, gusts 5 mph9 km/h	96%	78%	0
Sat 8a	Partly sunny	48°9° (likely 46°8° to 51°11°)	47°8°	0%	3 mph5 km/h from E, gusts 6 mph9 km/h	100%	84%	0
Sat 9a	Cloudy	54°12° (likely 53°12° to 55°13°)	54°12°	0%	3 mph5 km/h from SE, gusts 7 mph11 km/h	86%	70%	1
Sat 10a	Partly sunny	61°16° (likely 58°14° to 61°16°)	61°16°	0%	5 mph8 km/h from SE, gusts 9 mph15 km/h	70%	59%	2
Sat 11a	Partly sunny	66°19° (likely 63°17° to 67°19°)	66°19°	0%	5 mph8 km/h from SE, gusts 9 mph14 km/h	56%	65%	3
Sat 12p	Cloudy	70°21° (likely 67°19° to 71°22°)	70°21°	0%	5 mph8 km/h from SE, gusts 7 mph12 km/h	46%	76%	4
Sat 1p	Partly sunny	73°23° (likely 70°21° to 74°23°)	73°23°	0%	5 mph8 km/h from SE, gusts 7 mph11 km/h	40%	75%	4
Sat 2p	Partly sunny	74°23° (likely 72°22° to 75°24°)	74°23°	0%	5 mph8 km/h from SE, gusts 7 mph11 km/h	38%	59%	4
Sat 3p	Cloudy	75°24° (likely 72°22° to 76°24°)	75°24°	0%	5 mph8 km/h from SE, gusts 7 mph11 km/h	37%	61%	3
Sat 4p	Cloudy	76°24° (likely 72°22° to 76°24°)	76°24°	0%	5 mph8 km/h from SE, gusts 7 mph12 km/h	34%	59%	3
Sat 5p	Partly sunny	74°23° (likely 70°21° to 75°24°)	74°23°	0%	5 mph8 km/h from SE, gusts 8 mph13 km/h	38%	43%	1
Sat 6p	Clear	70°21° (likely 66°19° to 70°21°)	70°21°	0%	5 mph8 km/h from SE, gusts 8 mph13 km/h	44%	40%	0
Sat 7p	Clear	65°18° (likely 62°17° to 66°19°)	65°18°	0%	5 mph8 km/h from SE, gusts 7 mph12 km/h	54%	40%	0
Sat 8p	Clear	60°16° (likely 59°15° to 63°17°)	60°16°	0%	3 mph5 km/h from SE, gusts 7 mph11 km/h	64%	43%	0
Sat 9p	Partly cloudy	58°14° (likely 57°14° to 61°16°)	58°14°	0%	3 mph5 km/h from SE, gusts 8 mph13 km/h	69%	47%	0
Sat 10p	Partly cloudy	57°14° (likely 55°13° to 59°15°)	57°14°	0%	2 mph3 km/h from SE, gusts 9 mph14 km/h	72%	49%	0
Sat 11p	Partly cloudy	56°13° (likely 54°12° to 59°15°)	56°13°	0%	2 mph3 km/h from SE, gusts 10 mph16 km/h	72%	48%	0
Sun 12a	Partly cloudy	55°13° (likely 52°11° to 58°14°)	55°13°	0%	2 mph3 km/h from SE, gusts 10 mph15 km/h	74%	45%	0
Sun 1a	Clear	53°12° (likely 51°11° to 57°14°)	53°12°	0%	2 mph3 km/h from SE, gusts 9 mph14 km/h	80%	37%	0
Sun 2a	Partly cloudy	52°11° (likely 50°10° to 56°13°)	52°11°	0%	1 mph2 km/h from SE, gusts 8 mph13 km/h	83%	31%	0
Sun 3a	Mostly clear	51°11° (likely 49°9° to 55°13°)	51°11°	0%	1 mph2 km/h from SE, gusts 8 mph13 km/h	83%	21%	0
Sun 4a	Partly cloudy	50°10° (likely 49°9° to 53°12°)	50°10°	0%	1 mph2 km/h from SE, gusts 6 mph10 km/h	86%	23%	0
Sun 5a	Partly cloudy	50°10° (likely 48°9° to 52°11°)	50°10°	0%	1 mph2 km/h from SE, gusts 6 mph10 km/h	86%	41%	0
Sun 6a	Partly cloudy	49°9° (likely 47°8° to 52°11°)	49°9°	0%	1 mph2 km/h from SE, gusts 5 mph9 km/h	89%	41%	0
Sun 7a	Partly sunny	49°9° (likely 46°8° to 52°11°)	49°9°	0%	1 mph2 km/h from SE, gusts 5 mph8 km/h	89%	61%	0
Sun 8a	Partly sunny	50°10° (likely 46°8° to 55°13°)	50°10°	0%	1 mph2 km/h from SE, gusts 4 mph7 km/h	93%	45%	0
Sun 9a	Partly sunny	56°13° (likely 53°12° to 60°16°)	56°13°	0%	1 mph2 km/h from SE, gusts 6 mph9 km/h	80%	61%	1
Sun 10a	Cloudy	63°17° (likely 60°16° to 65°18°)	63°17°	0%	2 mph3 km/h from S, gusts 6 mph10 km/h	65%	74%	2
Sun 11a	Cloudy	68°20° (likely 66°19° to 69°21°)	68°20°	0%	2 mph3 km/h from S, gusts 7 mph11 km/h	55%	78%	3
Sun 12p	Cloudy	72°22° (likely 71°22° to 73°23°)	72°22°	0%	3 mph5 km/h from S, gusts 7 mph11 km/h	48%	77%	4

Days ahead

Shaded: typical range for these dates (1991–2020)

Today, Oct 23. Sunny. High 77°25°, low 47°8°. Typical 70°21° / 44°7°. Dry. Forecasts agree.
1. Afternoon
  noon–6 PM
  Sunny, 76°24°
  Dry
2. Evening
  6 PM–midnight
  Clear, 60°16°
  Dry
3. Overnight
  midnight–6 AM
  Partly cloudy, 48°9°
  Dry
Official NWS forecast
Today: Sunny, with a high near 77. Southeast wind around 6 mph.
Tonight: Mostly clear, with a low around 47. Southeast wind around 5 mph.
Forecasts agreeIndependent forecasts are close; the range is narrow.
High, likely
73°23°–77°25°
Low, likely
47°8°–48°9°
Typical high / low
70°21° / 44°7°
Wind
7 mph11 km/h, gusts 16 mph26 km/h
UV peak
5
Tomorrow, Oct 24. Cloudy. High 76°24°, low 49°9°. Typical 69°21° / 44°7°. Dry. Mostly agree.
1. Morning
  6 AM–noon
  Cloudy, 48°9°
  Dry
2. Afternoon
  noon–6 PM
  Cloudy, 76°24°
  Dry
3. Evening
  6 PM–midnight
  Partly cloudy, 60°16°
  Dry
4. Overnight
  midnight–6 AM
  Mostly clear, 50°10°
  Dry
Official NWS forecast
Day: Mostly sunny, with a high near 76. Southeast wind around 5 mph.
Night: Partly cloudy, with a low around 49. Southeast wind 1 to 5 mph.
Mostly agreeIndependent forecasts are fairly close; small surprises are possible.
High, likely
72°22°–76°24°
Low, likely
46°8°–49°9°
Typical high / low
69°21° / 44°7°
Wind
7 mph10 km/h, gusts 14 mph23 km/h
UV peak
4
Sunday, Oct 25. Partly sunny. High 78°26°, low 51°11°. Typical 69°21° / 44°7°. Dry. Forecasts agree.
1. Morning
  6 AM–noon
  Partly sunny, 50°10°
  Dry
2. Afternoon
  noon–6 PM
  Cloudy, 77°25°
  Dry
3. Evening
  6 PM–midnight
  Cloudy, 63°17°
  Dry
4. Overnight
  midnight–6 AM
  Cloudy, 55°13°
  Dry
Official NWS forecast
Day: Mostly sunny. High near 78, with temperatures falling to around 74 in the afternoon. South wind around 3 mph.
Night: Mostly cloudy, with a low around 51.
Forecasts agreeIndependent forecasts are close; the range is narrow.
High, likely
76°24°–78°26°
Low, likely
46°8°–52°11°
Typical high / low
69°21° / 44°7°
Wind
7 mph10 km/h, gusts 14 mph23 km/h
UV peak
4
Monday, Oct 26. Cloudy. High 78°26°, low 51°11°. Typical 68°20° / 44°7°. Dry. Forecasts agree.
1. Morning
  6 AM–noon
  Cloudy, 55°13°
  Dry
2. Afternoon
  noon–6 PM
  Cloudy, 76°24°
  Dry
3. Evening
  6 PM–midnight
  Cloudy, 63°17°
  Dry
4. Overnight
  midnight–6 AM
  Cloudy, 52°11°
  Dry
Hours this far out come from computer models only.
Official NWS forecast
Day: Partly sunny, with a high near 78.
Night: Partly cloudy, with a low around 51.
Forecasts agreeIndependent forecasts are close; the range is narrow.
High, likely
75°24°–78°26°
Low, likely
51°11°–56°13°
Typical high / low
68°20° / 44°7°
Wind
7 mph11 km/h, gusts 14 mph23 km/h
UV peak
3
Tuesday, Oct 27. Cloudy. High 77°25°, low 51°11°. Typical 68°20° / 43°6°. Dry. Forecasts agree.
1. Morning
  6 AM–noon
  Cloudy, 53°12°
  Dry
2. Afternoon
  noon–6 PM
  Cloudy, 72°22°
  Dry
3. Evening
  6 PM–midnight
  Cloudy, 62°17°
  Dry
4. Overnight
  midnight–6 AM
  Cloudy, 53°12°
  Dry
Hours this far out come from computer models only.
Official NWS forecast
Day: Partly sunny, with a high near 77.
Night: Mostly cloudy, with a low around 51.
Forecasts agreeIndependent forecasts are close; the range is narrow.
High, likely
71°22°–77°25°
Low, likely
47°8°–55°13°
Typical high / low
68°20° / 43°6°
Wind
8 mph12 km/h, gusts 21 mph33 km/h
UV peak
3
Wednesday, Oct 28. Cloudy. High 78°26°, low 53°12°. Typical 67°19° / 43°6°. Dry. Mostly agree.
1. Morning
  6 AM–noon
  Sunny, 55°13°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 77°25°
  Dry
3. Evening
  6 PM–midnight
  Clear, 64°18°
  Dry
4. Overnight
  midnight–6 AM
  Mostly clear, 54°12°
  Dry
Hours this far out come from computer models only.
Official NWS forecast
Day: Mostly sunny, with a high near 78.
Night: Mostly clear, with a low around 53.
Mostly agreeIndependent forecasts are fairly close; small surprises are possible.
High, likely
74°23°–79°26°
Low, likely
49°9°–55°13°
Typical high / low
67°19° / 43°6°
Wind
11 mph18 km/h, gusts 26 mph42 km/h
UV peak
4
Thursday, Oct 29. Partly sunny. High 77°25°, low 49°9°. Typical 67°19° / 43°6°. Dry. Forecasts differ.
1. Morning
  6 AM–noon
  Sunny, 55°13°
  Dry
2. Afternoon
  noon–6 PM
  Sunny, 73°23°
  Dry
3. Evening
  6 PM–midnight
  Clear, 61°16°
  Dry
4. Overnight
  midnight–6 AM
  Clear, 50°10°
  Dry
Hours this far out come from computer models only.
Official NWS forecast
Day: Mostly sunny, with a high near 77.
Night: Partly cloudy, with a low around 49.
Forecasts differIndependent forecasts disagree; expect changes and plan for the range.
High, likely
65°18°–81°27°
Low, likely
47°8°–56°13°
Typical high / low
67°19° / 43°6°
Wind
10 mph16 km/h, gusts 28 mph45 km/h
UV peak
4
Friday, Oct 30. Partly sunny. High 73°23°, low 53°12°. Typical 66°19° / 42°6°. Dry. Forecasts differ.
1. Morning
  6 AM–noon
  Sunny, 53°12°
  Dry
2. Afternoon
  noon–6 PM
  Cloudy, 73°23°
  Dry
3. Evening
  6 PM–midnight
  Cloudy, 63°17°
  Dry
4. Overnight
  midnight–6 AM
  Cloudy, 58°14°
  20% chance
Hours this far out come from computer models only.
The National Weather Service writes about seven days ahead; this day is our model forecast only.
Forecasts differIndependent forecasts disagree; expect changes and plan for the range.
High, likely
64°18°–78°26°
Low, likely
44°7°–59°15°
Typical high / low
66°19° / 42°6°
Wind
9 mph14 km/h, gusts 18 mph28 km/h
UV peak
3
Saturday, Oct 31. Drizzle. High 68°20°, low 57°14°. Typical 66°19° / 42°6°. Rain 0.2 in5.1 mm, 40% chance. Mostly agree.
1. Morning
  6 AM–noon
  Drizzle, 59°15°
  30% chance · 0.03 in0.7 mm
2. Afternoon
  noon–6 PM
  Drizzle, 65°18°
  40% chance · 0.05 in1.3 mm
3. Evening
  6 PM–midnight
  Cloudy, 63°17°
  40% chance · 0.08 in2 mm
4. Overnight
  midnight–6 AM
  Cloudy, 60°15°
  30% chance · 0.26 in6.7 mm
Hours this far out come from computer models only.
The National Weather Service writes about seven days ahead; this day is our model forecast only.
Mostly agreeIndependent forecasts are fairly close; small surprises are possible.
High, likely
65°18°–72°22°
Low, likely
50°10°–61°16°
Typical high / low
66°19° / 42°6°
Wind
16 mph25 km/h, gusts 24 mph38 km/h
Sunday, Nov 1. Showers. High 69°21°, low 60°16°. Typical 65°18° / 42°6°. Rain 0.65 in17 mm, 40% chance. Forecasts differ.
1. Morning
  6 AM–noon
  Cloudy, 61°16°
  30% chance · 0.33 in8.3 mm
2. Afternoon
  noon–6 PM
  Cloudy, 69°20°
  30% chance · 0.02 in0.5 mm
3. Evening
  6 PM–midnight
  Showers, 65°18°
  20% chance · 0.08 in2 mm
Hours this far out come from computer models only.
The National Weather Service writes about seven days ahead; this day is our model forecast only.
Forecasts differIndependent forecasts disagree; expect changes and plan for the range.
High, likely
65°18°–72°22°
Low, likely
55°13°–63°17°
Typical high / low
65°18° / 42°6°
Wind
14 mph22 km/h, gusts 26 mph42 km/h
UV peak
1

10 days15 days30 days

The outlook

Today
Dry, high 77°, low 47°.
Tomorrow
Dry, high 76°, low 49°.
Sunday
Dry, high 78°, low 51°.
Rest of week
Mostly dry, highs 68–78°.

Want the meteorologists’ reasoning? Read the NWS forecast discussion (LSX) (opens in a new tab)

What changed since yesterday

No meaningful changes from yesterday’s forecast.

Radar

Radar data: NOAA MRMS, rendered by forecast.blue

Radar loads when scrolled into view

Full-screen radar

Rivers

NOAA river gauges within 25 mi

Mississippi River at St. Louis

14 mi

Below flood stage

Level: 8.5 ft
Flow: 177,000 cfs

Forecast peak 8.5 ft Fri 7 PM

Reading from Fri 1 PM · NWS gauge page

Mississippi River at Mel Price (Alton) Lock and Dam

22 mi

Below flood stage

Level: 7.8 ft
Flow: 125,000 cfs

Forecast peak 7.8 ft Fri 7 PM

Reading from Fri 1 PM · NWS gauge page

Silver Creek near Mascoutah

7.1 mi

Level: 8.0 ft
Flow: 1,460 cfs

Reading from Fri 12:45 PM · NWS gauge page

Kaskaskia River at New Athens

19 mi

Below flood stage

Level: 68.6 ft
Flow: 426 cfs

Reading from Fri 12 PM · NWS gauge page

For your home

What this week’s weather means for heating, cooling, pipes and fresh air.

Heating this week

About 77% less heating than a typical week.

This week 15Typical 64

Heating degree days, base 65°F

Heat-pump hours, next 7 days

h below 47°F: 1
h below 17°F: 0
h below 5°F: 0

47, 17 and 5°F are the test points heat pumps are rated at.

Comfort

Dry air outside (dew point 46°F).

Open the windows?

Today, 2:00 PM–8:00 PM

Good stretch to open the windows.

Is this typical?

BELLEVILLE SIU RESEARCH · official normals 1991–2020 · records 1948–2026

Oct 23, today vs a typical year

Today’s expected high is 7°4° warmer than typical.

Last 7 days vs normal

On average 8°4° colder than normal (daily mean temperature).

−7°−4°SatOct 17
—SunOct 18
—MonOct 19
—TueOct 20
—WedOct 21
—ThuOct 22
—FriOct 23

O'Fallon weather by month: normals, records, snow and freeze dates

Sun & moon

Sun

Daylight: 10 h 53 min; Losing 2 min 21 s a day; shortest Dec 21, 1 h 25 min less
Golden hour: 5:33–6:26 PM; Morning 7:00–7:53 AM
Blue hour: 6:26–6:37 PM; Morning 6:49–7:00 AM; first light 6:49 AM

Stars tonight? Fair

Mostly clear 6:37 PM–12 AM, but the moon is 95% lit and up.

Moon

Waxing gibbous

93% lit · growing

Today: sets 4:25 AM · rises 4:40 PM
Full moon: Oct 25
New moon: Nov 9

Looking west from O'Fallon. The highest point on the skyline is about 3,200 ft, 17 mi away.Skyline from USGS elevation data, heights drawn up to 6× taller. Sky, sun and moon as they are now.

O'Fallon, IL weather

Next 2 hours

Next 48 hours

Days ahead

The outlook

Today

Tomorrow

Sunday

Rest of week

What changed since yesterday

Radar

Rivers

Mississippi River at St. Louis

Mississippi River at Mel Price (Alton) Lock and Dam

Silver Creek near Mascoutah

Kaskaskia River at New Athens

For your home

Heating this week

Heat-pump hours, next 7 days

Comfort

Open the windows?

Is this typical?

Oct 23, today vs a typical year

Last 7 days vs normal

Sun & moon

Sun

Stars tonight? Fair

Moon