Live Weather & Forecast

Weather in O’Fallon

Missouri, United States · Real-time conditions & 3-day outlook

Flag of United States
Partly cloudy
21°C
Feels like 21°C
70°F / Feels 70°F
Partly cloudy
O’Fallon, Missouri
🌞 Daytime
Updated: 2026-04-13 07:45
💧
Humidity
73%
💨
Wind
19.4 km/h SSW
🌬️
Wind Gust
31.7 km/h
🌡️
Pressure
1015 mb
👁️
Visibility
16 km
☀️
UV Index
0.1 (Low)
🌧️
Precipitation
0 mm
☁️
Cloud Cover
50%
💦
Dew Point
16.3°C
🌐
Wind Degree
207°

Air Quality Index

US EPA: Good UK DEFRA: Low (1)
CO
149.9 μg/m³
NO₂
2.5 μg/m³
O₃
81 μg/m³
SO₂
1.4 μg/m³
PM 2.5
3.7 μg/m³
PM 10
4.2 μg/m³

Weather Alerts 4

Met · Severe · Immediate
Flood Warning issued April 12 at 11:41AM CDT until April 20 at 7:00AM CDT by NWS St Louis MO

...The Flood Warning continues for the following river in Missouri and Illinois... Mississippi River at Hannibal Clarksville Louisiana River forecasts are based on observed precipitation and forecast precipitation for the next 24 hours. * WHAT...Minor flooding is occurring and minor flooding is forecast. * WHERE...Mississippi River at Clarksville. * WHEN...Until Monday, April 20. * ADDITI...

Motorists should not attempt to drive around barricades or drive cars through flooded areas. This product, along with additional weather and stream information, is available at https://water.noaa.gov/wfo/lsx

Effective: 2026-04-12T11:41:00-05:00  ·  Expires: 2026-04-13T23:45:00-05:00
Met · Severe · Immediate
Flood Warning issued April 12 at 9:46PM CDT until April 20 at 7:00AM CDT by NWS St Louis MO

...The Flood Warning continues for the following rivers in Illinois...Missouri... Mississippi River at Clarksville. Mississippi River at Louisiana. Mississippi River at Hannibal. River forecasts are based on observed precipitation and forecast precipitation for the next 24 hours. * WHAT...Minor flooding is occurring and minor flooding is forecast. * WHERE...Mississippi River at Clarksville....

Motorists should not attempt to drive around barricades or drive cars through flooded areas. This product, along with additional weather and stream information, is available at https://water.noaa.gov/wfo/lsx

Effective: 2026-04-12T21:46:00-05:00  ·  Expires: 2026-04-14T10:00:00-05:00
Met · Severe · Immediate
Flood Warning issued April 12 at 11:41AM CDT until April 20 at 7:00AM CDT by NWS St Louis MO

...The Flood Warning continues for the following river in Missouri and Illinois... Mississippi River at Hannibal Clarksville Louisiana River forecasts are based on observed precipitation and forecast precipitation for the next 24 hours. * WHAT...Minor flooding is occurring and minor flooding is forecast. * WHERE...Mississippi River at Louisiana. * WHEN...Until Monday, April 20. * ADDITION...

Motorists should not attempt to drive around barricades or drive cars through flooded areas. This product, along with additional weather and stream information, is available at https://water.noaa.gov/wfo/lsx

Effective: 2026-04-12T11:41:00-05:00  ·  Expires: 2026-04-13T23:45:00-05:00
Met · Severe · Immediate
Flood Warning issued April 12 at 9:46PM CDT until April 20 at 7:00AM CDT by NWS St Louis MO

...The Flood Warning continues for the following rivers in Illinois...Missouri... Mississippi River at Clarksville. Mississippi River at Louisiana. Mississippi River at Hannibal. River forecasts are based on observed precipitation and forecast precipitation for the next 24 hours. * WHAT...Minor flooding is occurring and minor flooding is forecast. * WHERE...Mississippi River at Louisiana. *...

Motorists should not attempt to drive around barricades or drive cars through flooded areas. This product, along with additional weather and stream information, is available at https://water.noaa.gov/wfo/lsx

Effective: 2026-04-12T21:46:00-05:00  ·  Expires: 2026-04-14T10:00:00-05:00

Today's Hourly Forecast

24-hour breakdown for O’Fallon, Missouri

12 AM
Clear
20°
Clear
💧 72% 💨 19.8 km/h
1 AM
Clear
20°
Clear
💧 76% 💨 19.8 km/h
2 AM
Partly Cloudy
20°
Partly Cloudy
💧 78% 💨 19.8 km/h
3 AM
Clear
20°
Clear
💧 77% 💨 17.3 km/h
4 AM
Clear
20°
Clear
💧 80% 💨 16.6 km/h
5 AM
Clear
20°
Clear
💧 82% 💨 18.4 km/h
6 AM
Partly Cloudy
19°
Partly Cloudy
💧 82% 💨 20.2 km/h
7 AM
Partly cloudy
21°
Partly cloudy
💧 73% 💨 19.4 km/h
8 AM
Partly Cloudy
21°
Partly Cloudy
💧 82% 💨 20.9 km/h
9 AM
Partly Cloudy
22°
Partly Cloudy
💧 78% 💨 20.9 km/h
10 AM
Partly Cloudy
24°
Partly Cloudy
💧 73% 💨 23.8 km/h
11 AM
Cloudy
25°
Cloudy
💧 69% 💨 24.8 km/h
12 PM
Overcast
27°
Overcast
💧 65% 💨 24.8 km/h
1 PM
Partly Cloudy
28°
Partly Cloudy
💧 59% 💨 24.8 km/h
2 PM
Partly Cloudy
29°
Partly Cloudy
💧 54% 💨 25.6 km/h
3 PM
Partly Cloudy
31°
Partly Cloudy
💧 50% 💨 25.2 km/h
4 PM
Sunny
31°
Sunny
💧 48% 💨 24.8 km/h
5 PM
Sunny
27°
Sunny
💧 47% 💨 24.1 km/h
6 PM
Thundery outbreaks in nearby
26°
Thundery outbreaks in nearby
💧 77% 💨 22 km/h
7 PM
Overcast
24°
Overcast
💧 72% 💨 24.8 km/h
8 PM
Overcast
24°
Overcast
💧 77% 💨 25.6 km/h
9 PM
Overcast
23°
Overcast
💧 76% 💨 24.5 km/h
10 PM
Cloudy
23°
Cloudy
💧 80% 💨 24.1 km/h
11 PM
Thundery outbreaks in nearby
23°
Thundery outbreaks in nearby
💧 76% 💨 24.8 km/h

3-Day Forecast

Daily overview for O’Fallon, Missouri

Today
Partly Cloudy
Partly Cloudy
32° / 19°
🌧️ 0% chance of rain
💧 Avg. humidity: 72%
💨 Max wind: 25.6 km/h
🌧️ Total precip: 0 mm
☀️ UV Index: 2
🌅 Sunrise: 06:29 AM
🌇 Sunset: 07:38 PM
🌙 Waning Crescent
🌑 Moon: 23% lit
Tue, Apr 14
Cloudy
Cloudy
27° / 20°
🌧️ 0% chance of rain
💧 Avg. humidity: 76%
💨 Max wind: 29.2 km/h
🌧️ Total precip: 0.09 mm
☀️ UV Index: 2
🌅 Sunrise: 06:27 AM
🌇 Sunset: 07:39 PM
🌙 Waning Crescent
🌑 Moon: 15% lit
Wed, Apr 15
Patchy rain nearby
Patchy rain nearby
22° / 20°
🌧️ 87% chance of rain
💧 Avg. humidity: 78%
💨 Max wind: 29.5 km/h
🌧️ Total precip: 3.47 mm
☀️ UV Index: 0.9
🌅 Sunrise: 06:26 AM
🌇 Sunset: 07:40 PM
🌙 Waning Crescent
🌑 Moon: 8% lit

Best Time to Visit O’Fallon

Plan your trip to O’Fallon, United States around the most favorable weather conditions.

Peak Season
June – September
Warm, dry summers — ideal for outdoor activities.
Shoulder Season
April – May, October
Fewer crowds, moderate prices, mild weather.
Off Season
November – March
Cooler temperatures; some regions may experience rain or snow.
← Back to O’Fallon 🗓 View Holidays 2026

Frequently Asked Questions

What is the current weather in O’Fallon?
Current conditions in O’Fallon: Partly cloudy, temperature 21°C, humidity 73%.
What is the best time to visit O’Fallon?
The best time to visit O’Fallon is typically June – September. Warm, dry summers — ideal for outdoor activities.
What is the climate like in O’Fallon?
O’Fallon is located at approximately 38.8° latitude. It has a temperate climate with warm summers and cold winters.
Does it rain a lot in O’Fallon?
The wettest period in O’Fallon is typically during November – March. Cooler temperatures; some regions may experience rain or snow.
What should I pack for a trip to O’Fallon?
For visits to O’Fallon during June – September: light clothing and sun protection. For November – March: layers and a waterproof jacket are recommended.
What country is O’Fallon in?
O’Fallon is located in United States, in the state of Missouri.
What are the public holidays in O’Fallon in 2026?
View the 2026 public holidays for O’Fallon on our Holidays page.
What are the GPS coordinates used for the weather forecast in O’Fallon?
The weather forecast for O’Fallon uses coordinates 38.7903, -90.7033.