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South Chicago weather

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South Chicago weather alerts and warnings

active National Weather Service watches, warnings and advisories

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South Chicago weather in numbers

measured normals and 10 years of recorded weather

South Chicago swings 58°F across the year, from 78°F highs in July to 20°F lows in January, and May is usually the wettest month in a year that brings about 43 in of precipitation. Over 10 years of recorded weather it averages 75 days a year at 77°F or above, 20 of them at 86°F or above, 103 frost nights, and rain on 133 days.

Warmest month
July
78°F average high
Coldest month
January
20°F average low
Wettest month
May
43 in a year
Comfortable
4 months
June, July, August and September
Residents
28,000
share this forecast
Most accurate here
European
90/100 CheckWeather Score
Warm days
75 days
a year at 77°F or above
Frost nights
103 nights
a year below 32°F
Rain days
133 days
a year with 0.04 in or more

Day counts are from the ERA5 reanalysis for South Chicago’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 South Chicago and nearby towns.Live rain radar →
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South Chicago 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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South Chicago 10-day forecast, out to 14 days

where the models agree, and where they split

South Chicago, Illinois (IL) is at its warmest in Jul (average highs near 78°F) and coldest in Jan (lows around 20°F), with roughly 43 in of precipitation across the year. Below, compare what NWS, American, European forecast for South Chicago 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.

South Chicago climate by month

average daytime high and overnight low across a typical year (1991-2020)
Jan
30°
20°
Feb
36°
21°
Mar
45°
31°
Apr
56°
40°
May
64°
48°
Jun
75°
60°
Jul
78°
65°
Aug
78°
65°
Sep
71°
58°
Oct
60°
46°
Nov
47°
35°
Dec
36°
26°

Source: 1991-2020 averages, ERA5 for this place adjusted with NASA POWER.

How the weather around South Chicago has changed since 1995

South Chicago sits in the same roughly 50 km square of NASA's reanalysis as Hammond. That square ran 1.5°F warmer in 2015-2024 than in 1995-2004. See the full 30-year picture on the Hammond page.

Which forecast is most accurate in South Chicago?

CheckWeather Score, graded against the weather that actually happened
ProviderCheckWeather-scoreTempWindRainRun by
European logo
European ★ Best
90
/100rank #1
81±1.9°F90±3.1 mph100100% hitECMWF - European Centre for Medium-Range Weather ForecastsReading, United Kingdom
American logo
American
79
/100rank #2
81±1.9°F94±1.8 mph6581% hitNOAA / NCEP (United States)College Park, Maryland, USA

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 counts

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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AmericanNOAA GFS
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EuropeanECMWF
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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.

Common questions

What's the weather in South Chicago today?
On this page we show what NWS, American, European each forecast for South Chicago 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 South Chicago today or tomorrow?
Check the hourly strip and 7-day forecast above. We compare rain from NWS, American, European for South Chicago 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 South Chicago?
Over the last 30 days, the European model has been the most accurate for South Chicago (CheckWeather Score 90/100), ahead of the American at 79. We grade every model against the recorded weather. See the US accuracy scoreboard for the full method.
What is the warmest month in South Chicago?
July is typically the warmest month in South Chicago, with average highs around 78°F.
How cold does South Chicago get?
The coldest month in South Chicago is January, when overnight lows average about 20°F.
How much rain does South Chicago get?
South Chicago sees roughly 43 in of precipitation a year, with May usually the wettest month.

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