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Chester weather in numbers
from 30 years of measured normals
Chester swings 63°F across the year, from 88°F highs in July to 25°F lows in January, and May is usually the wettest month in a year that brings about 47 in of precipitation.
Warmest month
July
88°F average high
Coldest month
January
25°F average low
Wettest month
May
47 in a year
Below freezing
3 months
January, February and December
Comfortable
2 months
April and October
Residents
8,588
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The weather map: all three models at once
NWS, American, European side by side around Chester and nearby towns.Live rain radar →
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Chester hourly forecast: next 14 hours
consensus of the three models
Rain in the next 24 hours, model by model
each model's own hourly precipitation, side by side
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Chester 10-day forecast, out to 14 days
where the models agree, and where they split
Chester, Illinois (IL) is at its warmest in Jul (average highs near 88°F) and coldest in Jan (lows around 25°F), with roughly 47 in of precipitation across the year. Below, compare what NWS, American, European forecast for Chester right now, and see exactly where they disagree.
average daytime high and overnight low across a typical year (1991-2020)
Jan
40°
25°
Feb
48°
27°
Mar
56°
36°
Apr
68°
47°
May
77°
57°
Jun
86°
65°
Jul
88°
70°
Aug
86°
69°
Sep
79°
61°
Oct
69°
49°
Nov
56°
38°
Dec
45°
30°
Source: 1991-2020 averages, ERA5 for this place adjusted with NASA POWER.
How Chester's weather has changed since 1995
30 years of daily data, 1995-2024, shown as change
+1.2°F
Around Chester, 2015-2024 averaged 1.2°F warmer than 1995-2004. 4 of the 10 warmest years since 1995 fall in the last ten, and the warmest was 2012.
1995each stripe is one year2024
cooler than averagearound averagewarmer than average
Days above 95°F
4 fewer days a year
2015-2024 against 1995-2004. Within the normal year-to-year swing
Frost nights
12 fewer nights a year
2015-2024 against 1995-2004, below 32°F. Within the normal year-to-year swing
Average wind
−1%
2015-2024 against 1995-2004. Within the normal year-to-year swing
Bars: each year against the area's 30-year average. Dashed lines: the average of the first and the last ten years.
See the numbers year by year
Year
Temp vs average
Days >95°F vs avg
Frost nights vs avg
Wind vs avg
1995
−1.4°F
−6
+12
−3%
1996
−2.3°F
−5
+19
+3%
1997
−2.0°F
−10
+11
−3%
1998
+1.4°F
−1
−16
+0%
1999
+0.7°F
+11
−5
+3%
2000
−0.4°F
+7
+8
+0%
2001
+0.7°F
+11
−1
−3%
2002
−0.2°F
+3
+8
+0%
2003
−0.9°F
+3
+8
+0%
2004
−0.4°F
−9
−5
+0%
2005
+0.7°F
+14
−5
−3%
2006
+0.7°F
+8
−8
+3%
2007
+0.9°F
+14
+12
−3%
2008
−2.2°F
−10
+23
+3%
2009
−1.6°F
−12
−2
+0%
2010
+0.2°F
+2
−3
−3%
2011
+0.2°F
+3
−5
+3%
2012
+3.1°F
+28
−16
+3%
2013
−2.0°F
−4
+23
+0%
2014
−2.3°F
−3
+25
+3%
2015
±0.0°F
−12
−18
−3%
2016
+1.1°F
−12
−7
−3%
2017
+2.0°F
+2
−19
+3%
2018
−0.4°F
−11
+14
−3%
2019
−0.5°F
−9
+7
+0%
2020
−0.2°F
−12
−13
−3%
2021
+0.5°F
−7
−5
+0%
2022
−0.4°F
+5
+12
+3%
2023
+2.2°F
+9
−23
−3%
2024
+2.5°F
+3
−25
+0%
Source: NASA POWER daily data from the MERRA-2 reanalysis, 1995-2024. Each value describes a grid square of about 50 km around Chester, not a weather station, and a square that takes in sea or a large lake runs milder than the city itself. That is why this section shows change against the square's own 30-year average rather than counts you could compare with a local station. Rain and snow are left out because their long-term record in this dataset is not consistent over time. "Within the normal year-to-year swing" means the change is smaller than the usual differences between single years.
Which forecast is most accurate in the US?
CheckWeather Score, graded against the weather that actually happened
Provider
CheckWeather-score
Temp
Wind
Rain
Run by
European ★ Best
93
/100rank #1
91±0.9°F
97±1.1 mph
9396% hit
ECMWF - European Centre for Medium-Range Weather ForecastsReading, United Kingdom
American
82
/100rank #2
83±1.7°F
94±2.0 mph
7184% hit
NOAA / NCEP (United States)College Park, Maryland, USA
The 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.
NWSNational Blend (NBM)
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Common questions
What's the weather in Chester today?
On this page we show what NWS, American, European each forecast for Chester today, side by side and updated live. When all three agree the forecast is reliable; when they split, we flag it so you know the day is genuinely less certain.
Will it rain in Chester today or tomorrow?
Check the hourly strip and 7-day forecast above. We compare rain from NWS, American, European for Chester and flag the days where the models disagree on whether showers actually arrive, which is exactly when a single app can catch you out.
Which forecast is most accurate for Chester?
No single model is always right. NWS, American, European each run their own physics, so we line all three up: when they agree the Chester forecast is reliable, and when they split you should expect surprises. See our tested US accuracy scoreboard for how the models compare.
What is the warmest month in Chester?
July is typically the warmest month in Chester, with average highs around 88°F.
How cold does Chester get?
The coldest month in Chester is January, when overnight lows average about 25°F.
How much rain does Chester get?
Chester sees roughly 47 in of precipitation a year, with May usually the wettest month.
Is Chester getting warmer?
Yes. In NASA's reanalysis for the area around Chester, 2015-2024 averaged 1.2°F warmer than 1995-2004.
