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Alton, IL Weather
Current conditions
Observed at St. Charles, St. Charles County Smartt Airport · 35 min ago
Forecast
10-day-
Friday
Sunny, with a high near 76.
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Friday Night
Mostly clear, with a low around 48.
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Saturday
Mostly sunny, with a high near 78.
National Weather Service forecast updated 2 days ago.
Hourly
Hourly forecast- Now74°
- 6 PM71°
- 7 PM65°
- 8 PM62°
- 9 PM60°
- 10 PM58°
- 11 PM56°
- Sat12 AM55°
- 1 AM54°
- 2 AM53°
- 3 AM52°
- 4 AM51°
- 5 AM49°
- 6 AM49°
- 7 AM49°
- 8 AM52°
- 9 AM56°
- 10 AM61°
- 11 AM66°
- 12 PM71°
- 1 PM75°
- 2 PM77°
- 3 PM78°
- 4 PM77°
10-day forecast
Details- TonightOct 20Mostly Clear46°
- WedOct 21Sunny49°75°
- ThuOct 22Sunny48°76°
- TodayOct 23Sunny48°76°
- SatOct 24Mostly Sunny50°78°
- SunOct 25Mostly Sunny52°80°
- MonOct 26Partly Sunny49°75°
- TueOct 27Partly Sunny68°
- WedOct 28Cloudy42°58°
- ThuOct 29Sunny38°56°
Days after the National Weather Service's seven are MET Norway's outlook, a computer model with no forecaster's review.
Radar
Full mapWeather news near Alton
More weather news- St. Louis Weather Forecast Friday Through Thursday
St. Louis is trading late-summer warmth for a blustery fall reset Friday: mostly cloudy skies, a high near 55, and northwest winds around 17 mph with gusts up to 33 mph. A few rain showers could move through after 3…
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Tracking a cool night, pleasant TuesdayTONIGHT: Mostly clear and cool with lows in the mid-40s. TOMORROW: Mostly sunny and mild with highs in the lower 70s. EXTENDED: We'll be cool again overnight as temperatures fall to the mid-40s. We'll see gradual…
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First Alert Weather Day Today: Low Severe Storm Chance 2 - 7PMKMOV - Outlying Areas Could See Frost Saturday AM and Sunday AM Today: Expect lots of cloud cover today with temperatures nearing 80°. Isolated Severe Storms Remain Possible this Afternoon from 2PM- 7PM: This is a…
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Damaging Winds Possible in Illinois and Missouri ThursdayParts of Missouri and most of Illinois are likely to experience the type of thunderstorm you'd expect to see during the Spring months. Forecasters are warning of a possible damaging wind event that will likely leave…
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This week's record heat caps hottest Jan.-Sept. on record in USIf it feels like summer never left, the numbers back you up. This week brought a fresh wave of record-breaking heat across the country, even as calendars flip toward Halloween. In a word: hot. According to U.S. National…
- Daily high-temperature records broken or tied on October 13 across parts of the central U.S.
Five daily high-temperature records were broken and one was tied at six sites across Kansas, Oklahoma, Missouri and Illinois on October 13, 2026. Temperatures at the sites reached 32.8–33.9°C (91–93°F), or 9.4–13.3°C…
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Tracking storms with heavy rain moving in late tonightTONIGHT: Warm with storms arriving late. Some storms may produce heavy rain and strong wind gusts. Lows in the upper 60s. TOMORROW: Rain and storms likely early, becoming more scattered by afternoon. Highs in the upper…
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Illinois to get brief taste of fall weather this weekMany different weather conditions are impacting Illinois this week. It started Monday with record heat. “Middle 90s in Metro East St. Louis,” said Meteorologist Paul Otto with Freese-Notis Weather during a Tuesday guest…
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A big cooldown will drop temperatures to their lowest levels in monthsA view of the Manhattan skyline illuminated at night, with autumn foliage in the foreground along the East River in New York City, on October 12. People visit Taughannock Falls State Park in Ithaca, New York, on October…
Air quality
People with heart or lung disease, older adults, children and teenagers should reduce prolonged or heavy exertion outdoors.
Forecast
- FriModerate
- SatModerate
- SunModerate
St. Louis (Metro-east), IL reporting area · 1 hr ago. Data from AirNow (EPA and its state, local and tribal partners); preliminary and subject to change.
Sun & moon
Almanac
MonthlySt Charles Elm Point, records since 1893. Normals 1991–2020. Data from NOAA's Regional Climate Centers (ACIS).
Nearby
- St. Louis 29 km
- O'Fallon 46 km
- Saint Charles 28 km
- Saint Peters 40 km
- Florissant 16 km
- Chesterfield 42 km
- Belleville 45 km
- Oakville 48 km
- Wildwood 54 km
- Wentzville 59 km
- University City 28 km
- Ballwin 45 km
Forecasters' discussion
From the National Weather Service office in LSX, issued 3 hrs ago
Key Messages
- High pressure remains in place allowing for our dry and warm weather continues well into next week.
Short Term
Issued at 148 PM CDT Fri Oct 23 2026
An upper-level ridge will remain positioned over the Mid-Mississippi River Valley through Sunday, stagnated by the configuration of the wave pattern into an Omega Block. This pattern will result in very little change in sensible weather from day to day with seasonably warm temperatures and dry conditions. The only change through the weekend will be the very slow departure of a surface high pressure center and upper-level clouds of varying thickness streaming overhead by Saturday through Sunday. The most pronounced nocturnal radiational cooling during the period will be across southeastern MO/southwestern IL and/or river valleys with low temperatures in the 40s F and patchy morning fog, mainly low temperatures in the 50s F elsewhere. High temperatures will continue to be in the 70s F, near 80 F on Sunday depending on the thickness of cloud cover.
Long Term
Issued at 148 PM CDT Fri Oct 23 2026
Global model guidance is coming into better agreement on the ejection of an upper-level trough into the Central/Northern Plains and Upper Midwest Monday through Tuesday as the Omega Block breaks down. With this track of the trough, it is increasingly likely that the associated cold front does not reach the CWA, favoring similar, seasonably warm temperatures continuing along with dry conditions.
It is not until late next week now, that there are any signs for our sensible weather to change with varying signals for an upper-level trough to propagate into the north-central CONUS. However, the track and amplitude of the trough is uncertain which will influence its ability to force an associated cold front east/southeastward. If the front reaches the CWA, it would be accompanied by an opportunity for rain and temperatures cooling closer to average late next week. If the front fails to reach the CWA, there would be no clear catalyst for seasonably warm temperatures and dry conditions to end. Ensemble model guidance cluster analysis depicts these scenarios all being valid possible outcomes at this point. Taking all scenarios into consideration, probabilities of measurable rainfall range from 20 to 50 percent Thursday, onward, along with NBM interquartile ranges increasing to between 10 and 20 F.
Aviation
Issued at 1147 AM CDT Fri Oct 23 2026
Aside from another round of fog in area river valleys Saturday morning potentially impacting KSUS and KCPS, dry and VFR flight conditions will prevail. Winds are expected to remain light and either southerly/southeasterly or variable.
Forecasts, observations and alerts in the United States come from the National Weather Service (NOAA); radar from NOAA's Multi-Radar Multi-Sensor system; satellite imagery from NASA's Global Imagery Browse Services (GIBS) and NOAA's GOES satellites; the map from the U.S. Geological Survey's National Map; air quality from AirNow (EPA and its partners); hurricane information from the National Hurricane Center; climate normals and records from NOAA's Regional Climate Centers (ACIS). Forecasts outside the United States and the UV index: MET Norway (CC BY 4.0); observations outside the U.S.: airport reports via NOAA's Aviation Weather Center. Place names: GeoNames (CC BY 4.0). Data are copied on a schedule and may lag the sources; for warnings that affect your safety, follow your local National Weather Service office and emergency officials. Weather news is drawn from the 4Conservative index and reflects what the press published. Terms of use.