Live Weather & Forecast
Weather in Alton
Illinois, United States · Real-time conditions & 3-day outlook
21°C
Feels like 21°C
70°F / Feels 70°F
Partly cloudy
Alton, Illinois
🌙 Nighttime
Updated: 2026-04-13 01:00
Humidity
70%
Wind
20.5 km/h SSW
Wind Gust
34 km/h
Pressure
1015 mb
Visibility
16 km
UV Index
0
(Low)
Precipitation
0 mm
Cloud Cover
75%
Dew Point
15.8°C
Wind Degree
200°
Air Quality Index
US EPA: Good
UK DEFRA: Low (1)
CO
137.9 μg/m³
NO₂
5.6 μg/m³
O₃
75 μg/m³
SO₂
2.4 μg/m³
PM 2.5
3.8 μg/m³
PM 10
3.9 μg/m³
Weather Alerts 1
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
Today's Hourly Forecast
24-hour breakdown for Alton, Illinois
12 AM
20°
Clear
1 AM
21°
Partly cloudy
2 AM
19°
Clear
3 AM
19°
Clear
4 AM
19°
Clear
5 AM
19°
Clear
6 AM
19°
Clear
7 AM
19°
Overcast
8 AM
20°
Overcast
9 AM
21°
Overcast
10 AM
23°
Partly Cloudy
11 AM
25°
Partly Cloudy
12 PM
24°
Partly Cloudy
1 PM
24°
Thundery outbreaks in nearby
2 PM
24°
Thundery outbreaks in nearby
3 PM
24°
Thundery outbreaks in nearby
4 PM
23°
Thundery outbreaks in nearby
5 PM
23°
Thundery outbreaks in nearby
6 PM
23°
Thundery outbreaks in nearby
7 PM
23°
Thundery outbreaks in nearby
8 PM
23°
Thundery outbreaks in nearby
9 PM
23°
Overcast
10 PM
22°
Thundery outbreaks in nearby
11 PM
21°
Thundery outbreaks in nearby
3-Day Forecast
Daily overview for Alton, Illinois
Today
Thundery outbreaks in nearby
27°
/
19°
🌧️ 0% chance of rain
💧 Avg. humidity: 78%
💨 Max wind: 29.2 km/h
🌧️ Total precip: 0 mm
☀️ UV Index: 1.9
🌅 Sunrise: 06:27 AM
🌇 Sunset: 07:36 PM
🌙 Waning Crescent
🌑 Moon: 23% lit
Tue, Apr 14
Thundery outbreaks in nearby
28°
/
20°
🌧️ 0% chance of rain
💧 Avg. humidity: 74%
💨 Max wind: 29.2 km/h
🌧️ Total precip: 0.03 mm
☀️ UV Index: 2
🌅 Sunrise: 06:25 AM
🌇 Sunset: 07:37 PM
🌙 Waning Crescent
🌑 Moon: 15% lit
Wed, Apr 15
Thundery outbreaks in nearby
23°
/
20°
🌧️ 0% chance of rain
💧 Avg. humidity: 76%
💨 Max wind: 29.2 km/h
🌧️ Total precip: 0 mm
☀️ UV Index: 0.9
🌅 Sunrise: 06:24 AM
🌇 Sunset: 07:38 PM
🌙 Waning Crescent
🌑 Moon: 8% lit
Best Time to Visit Alton
Plan your trip to Alton, 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.
Frequently Asked Questions
What is the current weather in Alton?
Current conditions in Alton: Partly cloudy, temperature 21°C, humidity 70%.
What is the best time to visit Alton?
The best time to visit Alton is typically June – September. Warm, dry summers — ideal for outdoor activities.
What is the climate like in Alton?
Alton is located at approximately 38.9° latitude. It has a temperate climate with warm summers and cold winters.
Does it rain a lot in Alton?
The wettest period in Alton is typically during November – March. Cooler temperatures; some regions may experience rain or snow.
What should I pack for a trip to Alton?
For visits to Alton during June – September: light clothing and sun protection. For November – March: layers and a waterproof jacket are recommended.
What country is Alton in?
Alton is located in United States, in the state of Illinois.
What are the public holidays in Alton in 2026?
View the 2026 public holidays for Alton on our Holidays page.
What are the GPS coordinates used for the weather forecast in Alton?
The weather forecast for Alton uses coordinates 38.8909, -90.1843.