Weather for Alton, Illinois
Current Weather
Five Day Weather Forecast
Mon
H: 86°F
L: 66°F
Tue
H: 84°F
L: 60°F
Wed
H: 66°F
L: 55°F
Thu
H: 62°F
L: 55°F
Fri
H: 66°F
L: 56°F
Air Quality
Nitrogen Dioxide: 2.05 μg/m3
Sulphur Dioxide: 2.65 μg/m3
Ozone: 93 μg/m3
Astronomical
Sun Transit: 12:57 AM
Sunset: 8:09 PM
Daylight: 14 hrs 24 mins
Moon Transit: 2:57 PM
Moonset: 10:59 PM
Moon Phase: New
Moon Illumination: 2.6%
Best Times for Fishing or Hunting
Major Periods
1:52 AM - 4:22 AM2:27 PM - 4:57 PM
Minor Periods
10:29 PM - 11:59 PM6:26 AM - 7:56 AM
Action Rating: 3 out of 5
Severe Thunderstorm Warning issued May 18 at 7:21AM CDT until May 18 at 8:00AM CDT by NWS St Louis MO
Effective: Mon May 18, 2026, 7:21 AM
Expires: Mon May 18, 2026, 8:00 AM
SVRLSX The National Weather Service in St Louis has issued a * Severe Thunderstorm Warning for... Central Calhoun County in southwestern Illinois... Southwestern Greene County in southwestern Illinois... West Central Jersey County in southwestern Illinois... Northeastern Lincoln County in east central Missouri... Southeastern Pike County in northeastern Missouri... * Until 800 AM CDT. * At 721 AM CDT, a severe thunderstorm was located near Elsberry, moving east at 35 mph. HAZARD...60 mph wind gusts and small hail. SOURCE...Radar indicated. IMPACT...Expect damage to roofs, siding, and trees. * Locations impacted include... New Hope, Annada, Elsberry, Mozier, Hamburg, Hardin, Michael, Kampsville, Nutwood, Eldred, Fieldon and Woody.
Seek shelter inside a well-built structure and stay away from windows. This storm is capable of producing damaging winds. Tornadoes can develop quickly from severe thunderstorms. Seek shelter immediately in an interior room on the lowest floor of a well-built structure.
Flood Warning issued May 17 at 9:58AM CDT until May 20 at 1:00AM CDT by NWS St Louis MO
Effective: Sun May 17, 2026, 9:58 AM
Expires: Mon May 18, 2026, 10:00 PM
...The Flood Warning is extended for the following rivers in Illinois... Kaskaskia River at Carlyle. 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...Kaskaskia River at Carlyle. * WHEN...Until late Tuesday night. * ADDITIONAL DETAILS... - At 9:30 AM CDT Sunday the stage was 18.8 feet. - Recent Activity...The maximum river stage in the 24 hours ending at 9:30 AM CDT Sunday was 19.2 feet. - Forecast...The river is expected to fall below flood stage tomorrow evening and continue falling to 11.6 feet Sunday, May 24. - Flood stage is 16.5 feet.
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
Flood Warning issued May 17 at 8:16PM CDT until May 19 at 8:30PM CDT by NWS St Louis MO
Effective: Sun May 17, 2026, 8:16 PM
Expires: Tue May 19, 2026, 8:30 AM
...The Flood Warning continues for the following rivers in Illinois... Kaskaskia River at Carlyle. 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...Kaskaskia River at Carlyle. * WHEN...Until Tuesday evening. * ADDITIONAL DETAILS... - At 8:00 PM CDT Sunday the stage was 18.2 feet. - Recent Activity...The maximum river stage in the 24 hours ending at 8:00 PM CDT Sunday was 18.8 feet. - Forecast...The river is expected to fall below flood stage early tomorrow afternoon and continue falling to 12.8 feet Sunday, May 24. - Flood stage is 16.5 feet.
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
Weather Forecast
Air Quality
Nitrogen Dioxide: 5.34 μg/m3
Sulphur Dioxide: 2.3 μg/m3
Ozone: 79.04 μg/m3
Astronomical
Sun Transit: 12:57 AM
Sunset: 8:09 PM
Daylight: 14 hrs 24 mins
Moon Transit: 2:57 PM
Moonset: 10:59 PM
Moon Phase: New
Moon Illumination: 2.6%
Best Times for Fishing or Hunting
Major Periods
1:52 AM - 4:22 AM2:27 PM - 4:57 PM
Minor Periods
10:29 PM - 11:59 PM6:26 AM - 7:56 AM
Action Rating: 3 out of 5
Weather Forecast
Air Quality
Nitrogen Dioxide: 6.88 μg/m3
Sulphur Dioxide: 2.58 μg/m3
Ozone: 67.92 μg/m3
Astronomical
Sun Transit: 12:57 AM
Sunset: 8:10 PM
Daylight: 14 hrs 25 mins
Moon Transit: 4:03 PM
Moonset: 11:56 PM
Moon Phase: Waxing Crescent
Moon Illumination: 7.4%
Best Times for Fishing or Hunting
Major Periods
2:59 AM - 5:29 AM3:33 PM - 6:03 PM
Minor Periods
12:00 AM - 12:00 AM7:35 AM - 9:05 AM
Action Rating: 3 out of 5
Weather Forecast
Air Quality
Nitrogen Dioxide: 6.08 μg/m3
Sulphur Dioxide: 1.86 μg/m3
Ozone: 60.68 μg/m3
Astronomical
Sun Transit: 12:57 AM
Sunset: 8:11 PM
Daylight: 14 hrs 27 mins
Moon Transit: 5:05 PM
Moonset: 12:56 AM
Moon Phase: Waxing Crescent
Moon Illumination: 14.4%
Best Times for Fishing or Hunting
Major Periods
4:04 AM - 6:34 AM4:35 PM - 7:05 PM
Minor Periods
8:50 AM - 10:20 AM12:00 AM - 12:00 AM
Action Rating: 2 out of 5
Weather Forecast
Air Quality
Nitrogen Dioxide: 7.06 μg/m3
Sulphur Dioxide: 2.23 μg/m3
Ozone: 69.68 μg/m3
Astronomical
Sun Transit: 12:57 AM
Sunset: 8:12 PM
Daylight: 14 hrs 29 mins
Moon Transit: 6:01 PM
Moonset: 12:41 AM
Moon Phase: Waxing Crescent
Moon Illumination: 23.2%
Best Times for Fishing or Hunting
Major Periods
5:03 AM - 7:33 AM5:31 PM - 8:01 PM
Minor Periods
10:06 AM - 11:36 AM12:11 AM - 1:41 AM
Action Rating: 3 out of 5
Weather Forecast
Air Quality
Nitrogen Dioxide: 10.02 μg/m3
Sulphur Dioxide: 2.15 μg/m3
Ozone: 59 μg/m3
Astronomical
Sun Transit: 12:57 AM
Sunset: 8:13 PM
Daylight: 14 hrs 30 mins
Moon Transit: 6:52 PM
Moonset: 1:15 AM
Moon Phase: Waxing Crescent
Moon Illumination: 33.4%
Best Times for Fishing or Hunting
Major Periods
5:56 AM - 8:26 AM6:22 PM - 8:52 PM
Minor Periods
11:18 AM - 12:48 AM12:45 AM - 2:15 AM
Action Rating: 3 out of 5