Alton weather
Loading live data…Latest for Alton: NWS (National Blend (NBM)): 57° Mainly clear · American (NOAA GFS): 52° Clear · European (ECMWF): 56° Partly cloudy.
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active National Weather Service watches, warnings and advisoriesChecking the National Weather Service for active alerts covering Alton…
Alton weather in numbers
measured normals and 10 years of recorded weatherAlton swings 63°F across the year, from 87°F highs in July to 24°F lows in January, and May is usually the wettest month in a year that brings about 41 in of precipitation. Over 10 years of recorded weather it averages 136 days a year at 77°F or above, 59 of them at 86°F or above, 77 frost nights, and rain on 126 days.
Day counts are from the ERA5 reanalysis for Alton’s grid square, 2016 to 2025, counted the same way for every city so the numbers compare. A reanalysis square is an area, not a weather station, so it is good for counting days and not for a single day’s record.
The weather map: all three models at once
NWS, American, European side by side around Alton and nearby towns.Live rain radar →Alton hourly forecast: next 14 hours
consensus of the three modelsRain in the next 24 hours, model by model
each model's own hourly precipitation, side by sideLoading the three models…
Alton 10-day forecast, out to 14 days
where the models agree, and where they splitAlton, Illinois (IL) is at its warmest in Jul (average highs near 87°F) and coldest in Jan (lows around 24°F), with roughly 41 in of precipitation across the year. Below, compare what NWS, American, European forecast for Alton right now, and see exactly where they disagree.
We grade every model against the weather that actually happened, so you can see which forecast model is most accurate in United States before you trust any single number.
Alton climate by month
average daytime high and overnight low across a typical year (1991-2020)Source: 1991-2020 averages, ERA5 for this place adjusted with NASA POWER.
How the weather around Alton has changed since 1995
Alton sits in the same roughly 50 km square of NASA's reanalysis as Upper Alton. That square shows no clear change in temperature between 1995-2004 and 2015-2024. See the full 30-year picture on the Upper Alton page.
Which forecast is most accurate in Alton?
CheckWeather Score, graded against the weather that actually happened
The CheckWeather Score blends temperature, wind and rain accuracy, each measured against ERA5 (the recorded weather) over the last 30 days across 1999 cities. Lower error means a higher score. See which forecast model is most accurate in United States, how we measure forecast accuracy, or which model each weather app uses.
What do you think of the forecasts?
your vote countsThe accuracy above is the measured record. This is your opinion: which forecast service do you trust most in United States? Give each 1 to 5 stars.
One vote per service. Anonymous: we store no personal data, only a one-way hash of your connection for a day to stop double votes.