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Alton, IL Weather
Current conditions
Observed at St. Louis Regional Airport · 54 min ago
Forecast
10-day-
Thursday Night
Clear, with a low around 48. East wind around 3 mph.
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Friday
Sunny, with a high near 76.
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Friday Night
Mostly clear, with a low around 48.
National Weather Service forecast updated 2 days ago.
Hourly
Hourly forecast- Now52°
- 4 AM51°
- 5 AM49°
- 6 AM48°
- 7 AM48°
- 8 AM51°
- 9 AM56°
- 10 AM62°
- 11 AM67°
- 12 PM71°
- 1 PM73°
- 2 PM76°
- 3 PM76°
- 4 PM76°
- 5 PM74°
- 6 PM71°
- 7 PM65°
- 8 PM62°
- 9 PM60°
- 10 PM58°
- 11 PM56°
- Sat12 AM55°
- 1 AM54°
- 2 AM53°
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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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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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.
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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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Air quality
Acceptable. Unusually sensitive people should consider limiting prolonged outdoor exertion.
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 2 hrs ago
Key Messages
- Dry and seasonably warm conditions will persist through the weekend.
Short Term
Issued at 219 PM CDT Thu Oct 22 2026
A slow-moving upper-level ridge will dominate the Mid-Mississippi River Valley through the weekend with dry conditions continuing and only slight variations in above average temperatures. With a gradual exit of the surface high pressure center extending into the CWA this afternoon, the balance of airmass modification and subtle southeasterly low-level CAA through Friday followed by waves of upper-level clouds on Saturday and Sunday combined with weak southerly WAA will contribute to only slight fluctuations of high temperatures within the 70s F. Each night, the most favorable radiational cooling and coolest low temperatures in the 40s F will also become more and more confined to river valleys and southeastern MO/southwestern IL, closest to the high pressure and where clouds will be less prevalent and/or thinner. Patchy river valley fog is expected again Friday morning and potentially Saturday morning but coverage should be less.
Long Term
Issued at 219 PM CDT Thu Oct 22 2026
Global model guidance diverges considerably early to mid-next week in the evolution of an upper-level trough that propagates into the central CONUS Monday into Tuesday as the Omega Block breaks down. The track, amplitude, and tilt of this trough vary across guidance including whether an associated cold front passes through the CWA Tuesday or early Wednesday, enters and then stalls in the CWA, or stalls before reaching the CWA altogether. Accordingly, the NBM interquartile range increases to between 7 and 15 F Tuesday onward, with the 75th percentile remaining steady and the 25th percentile cooling closer to average. If the front reaches the CWA, showers will also become possible, with greatest probabilities of measurable rainfall in global ensemble models across central/northeastern MO and west-central IL at 30 to 50 percent. However, a widespread, substantial rainfall appears unlikely in the ranges of current scenarios. The aforementioned uncertainties persist through the end of the forecast period, late next week.
Aviation
Issued at 1233 AM CDT Fri Oct 23 2026
VFR conditions continue with light winds as high pressure remains in place across the region. The only question is whether valley fog will occur in the morning. With a calm wind near the center of high pressure, this is most likely to occur at SUS or CPS, though potentially JEF as well.
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 4Search index and reflects what the press published. Terms of use.