Chicago, IL Climate: Temperature & Rain by Month
Temperature and precipitation from NOAA NCEI 1991–2020 normals →, plus PlainClimate's derived comfort score
30-year climate normals (1991-2020) from Chicago's primary NOAA station, CHICAGO OHARE INTL AP.
The climate verdict for Chicago
Chicago, Illinois has a mixed annual climate rather than one dominant extreme. Its NOAA normal shows an annual average of 51°F. Its climate comfort score of 63/100 (good) lands mid-pack nationally, exceeding 46% of station-mapped location scores.
- 51°F
- annual average temperature (NOAA normal)
- 63/100
- comfort score, above 46% of station-mapped location scores
- 37.9"
- annual precipitation · 38" snow
- 195 days
- growing season, frost-free days
Chicago: NOAA 1991-2020 normals describe a typical year, not a forecast. Method: /methodology.
Normals record plate
Sheet USW00094846 · Chicago, IL 51°F mean · 37.9" precip
TEMP-COOL · RANK-MID · PHOTO-FINISH · PRCP-MID · SWING-WIDE · COMF-MID · LOAD-HEAT · STN-1 · BOOK-FULL
- TEMP-COOL 51°F
- RANK-MID #3,156
- PHOTO-FINISH ≈ Haigler
- PRCP-MID 37.9"
- SWING-WIDE 50°F
- COMF-MID 63/100
- LOAD-HEAT 5,974 HDD
- STN-1 USW00094846
- BOOK-FULL 6/6 fields
Nearest mean-temperature peer: Haigler, NE (+ 0 °F mean)
Instrument codes from this station's NOAA 1991–2020 normals, mean temperature, corpus warmth rank, photo-finish peer station, precipitation band, seasonal swing, comfort composite, degree-day load, and field book, not a livability rating.
Mean-temperature neighbourhood
Nationwide NOAA normal poles and nearest peers, not a reprint of every IL station list.
- Chicago (this station) 51°F
- Hot Imperial, NE 51°F
- Near Haigler, NE 51°F
- Near Kankakee Metro…, IL 51°F
- Near Elsmere, NE 51°F
Climate Living Index · Chicago
Chicago: 59/100 · grade C
Chicago publishes all six Living Index dimensions from NOAA annual/seasonal normals · NOAA daily multivariate normals · NOAA hourly normals.
PlainClimate-derived for Chicago, not an official NOAA rating. Rankings still use Comfort Score 63/100 (separate formula). Breakpoints and limits.
| Dimension | Station value | Score |
|---|---|---|
| Precipitation balance | 37.9 in · 2.9 from 35 in | 89/100 · A |
| Normal heat + freeze calendar | 120 calendar days | 65/100 · C |
| Frost-free season | 195 days/year | 61/100 · C |
| Summer moisture balance | 60.9°F mean dew point | 56/100 · C |
| Annual temperature balance | 51.2°F · 16.3° from 67.5°F | 46/100 · D |
| Snowfall burden | 38.4 inches/year | 30/100 · F |
Chicago · 2026-08-04 · NOAA NCEI Climate Normals · method · Comfort Score method.
Chicago is a continental Köppen climate: Dfa
Coldest-month mean 25.2°F and warmest-month mean 75.4°F place this station in continental, no dry season, hot summer climates (Dfa). Class Dfa is the Peel et al. (2007) label for this station's monthly mean temperature and precipitation normals: continental, specifically continental, no dry season, hot summer.
- Köppen code
- Dfa
- Group
- Continental
- Warmest month
- 75.4°F
- Coldest month
- 25.2°F
Source: official public datasets monthly normals (1991–2020) at the city’s primary station. This is a station classification, not a mapped regional consensus.
National standing · heating-led station
Where Chicago sits across the climate record
Three NOAA fields for Chicago's primary station, temperature, precipitation, and seasonal swing, are ranked against every station-mapped normal that carries the same field.
- Annual temperature
- 46th percentile warmth
- Mid-pack annual mean versus 6,861 station normals.
- Annual precipitation
- 53rd percentile wetness
- Neither arid nor torrential versus 6,352 station totals.
- Seasonal temperature swing
- Wider than 81%
- Warmest-to-coldest month gap for Chicago is large versus 6,861 complete station-years.
How Chicago compares across U.S. station-mapped locations
Chicago's comfort score vs. all station-mapped locations
PlainClimate composite comfort index (1–100), NOAA 1991–2020 normals
63 46th percentile score exceeds 46% of 6,189 station-mapped location scores
- 0–10: 0 station-mapped locations (0%). Below this entry.
- 10–20: 0 station-mapped locations (0%). Below this entry.
- 20–30: 96 station-mapped locations (2%). Below this entry.
- 30–40: 280 station-mapped locations (5%). Below this entry.
- 40–50: 1,113 station-mapped locations (18%). Below this entry.
- 50–60: 1,329 station-mapped locations (21%). Below this entry.
- 60–70: 1,236 station-mapped locations (20%). This entry sits in this band.
- 70–80: 650 station-mapped locations (11%). Above this entry.
- 80–90: 921 station-mapped locations (15%). Above this entry.
- 90–100: 564 station-mapped locations (9%). Above this entry.
Source NOAA U.S. Climate Normals, PlainClimate comfort index · 1991–2020
Chicago's measured station temperature trend
MethodologyAcross 71 complete annual observations from 1948 to 2025, CHICAGO OHARE INTL AP warmed at a fitted rate of 0.23°C per decade. The line shows the fitted change relative to its first year, not raw year-to-year temperatures or a forecast.
- Chicago primary station fitted change +0.23 °C/decade
Monthly Temperatures
Average daily high and low temperatures by month
| Month | Avg High | Avg Low | Mean | Precip | Snow | Freeze Days | 90°F+ Days |
|---|---|---|---|---|---|---|---|
| January | 32°F (0°C) | 19°F (-7°C) | 25°F (-4°C) | 2.0" | 11.3" | 28.1 | 0.0 |
| February | 36°F (2°C) | 22°F (-6°C) | 29°F (-2°C) | 2.0" | 10.7" | 24.4 | 0.0 |
| March | 47°F (8°C) | 31°F (-1°C) | 39°F (4°C) | 2.5" | 5.5" | 19.9 | 0.0 |
| April | 59°F (15°C) | 40°F (5°C) | 50°F (10°C) | 3.8" | 1.3" | 6.0 | 0.0 |
| May | 71°F (21°C) | 51°F (10°C) | 61°F (16°C) | 4.5" | 0.0" | 0.2 | 0.8 |
| June | 80°F (27°C) | 61°F (16°C) | 71°F (21°C) | 4.1" | 0.0" | 0.0 | 4.1 |
| July | 85°F (29°C) | 66°F (19°C) | 75°F (24°C) | 3.7" | 0.0" | 0.0 | 6.5 |
| August | 83°F (28°C) | 65°F (18°C) | 74°F (23°C) | 4.3" | 0.0" | 0.0 | 3.7 |
| September | 76°F (24°C) | 57°F (14°C) | 66°F (19°C) | 3.2" | 0.0" | 0.1 | 1.6 |
| October | 63°F (17°C) | 45°F (7°C) | 54°F (12°C) | 3.4" | 0.2" | 2.7 | 0.0 |
| November | 48°F (9°C) | 34°F (1°C) | 41°F (5°C) | 2.4" | 1.8" | 14.5 | 0.0 |
| December | 37°F (3°C) | 24°F (-4°C) | 31°F (-1°C) | 2.1" | 7.6" | 25.4 | 0.0 |
The year, day by day
Summer here tops out rather than builds: the warmest normal high is 85°F around July 11, short of 90°F on every date, while 120 dates carry a normal low at or below freezing, the coldest 18°F near January 23.
The freezing stretch
The normal low stays at or below 32°F into March 19, then returns to freezing around November 21, covering 120 dates in all.
Derived from the normal daily minimum. This is a different measure from the 50%-probability frost dates shown elsewhere on this page, which come from NOAA’s frost product.
Where the wet dates fall
The likeliest wet date is April 28, when 42% of years recorded at least a hundredth of an inch. The driest is September 2 at 28%. Summed across the calendar, that is about 126 wet dates a year.
The widest day
May 25 carries the biggest normal gap between afternoon and dawn, 20°F between the normal high and the normal low.
Look up any date
Any date's 1991–2020 normal for Chicago.
Where Chicago Stands Nationally
Among the steadiest day-night climates ranked: even the widest normal daily swing holds to roughly 20°F.
Chicago earns one nationally notable standing (outer quintile) against 6,860 NOAA 1991–2020 normals stations, middle-of-the-pack metrics stay silent here.
Monthly Precipitation
Average monthly rainfall and snowfall
Snow: 11.3"
11.0 days with precipitation
Snow: 10.7"
9.4 days with precipitation
Snow: 5.5"
10.8 days with precipitation
Snow: 1.3"
12.3 days with precipitation
12.5 days with precipitation
11.1 days with precipitation
9.7 days with precipitation
9.4 days with precipitation
8.5 days with precipitation
Snow: 0.2"
10.5 days with precipitation
Snow: 1.8"
10.0 days with precipitation
Snow: 7.6"
10.6 days with precipitation
Chicago spreads its precipitation across the year
Neither half of the year dominates here: June through August take 32% of the annual total and December through February 16%, with neither reaching the 35% that would mark a distinct wet season. Chicago has no dry season to plan around, though it does carry a wide 50.2°F gap between its warmest and coldest month.
The gap between the wettest and driest month still matters: May averages 4.5" and February 2.0". The three wettest months together take 34% of the year, against the 25% a perfectly flat distribution would give them.
Shares are computed from this station's own 1991-2020 monthly precipitation normals. "Spread across the year" means neither the June-August nor the December-February share reaches 35%; it describes an average year, not the variability of any single one.
How Chicago's precipitation splits across the calendar
About 126 days a year record measurable precipitation here, carrying 37.9" between them, or roughly 0.30 inches on a typical wet day. That sits in the middle band: neither the many-light-days pattern of the Pacific Northwest and the Great Lakes, nor the few-heavy-events pattern of the Gulf and the desert Southwest.
A wet day is one recording at least 0.01 inches. These are 1991-2020 normals: they describe an average year and say nothing about the heaviest single storm on record.
Winter brings real snow to Chicago
Chicago averages 38.4 inches of snowfall a year, with January the snowiest month on the normals, spread across roughly 28 days that record measurable snow. That is depth accumulating on the ground, which is why it can exceed the annual precipitation figure: precipitation counts the liquid the snow melts down to, and fresh snow is mostly air.
- Annual snowfall: 38.4 inches of depth.
- Days recording measurable snow: about 28 a year.
- At a rough ten-to-one melt ratio, snow accounts for on the order of 10% of the year's precipitation.
NOAA 1991-2020 normals. The ten-to-one ratio is a convention, not a measurement: real ratios vary with temperature, so treat the share as an order of magnitude rather than an exact split.
Frost Dates & Growing Season
First Fall Freeze
October 28
50% probability date
Last Spring Freeze
April 16
50% probability date
Growing Season
195 days
Heating & Cooling Degree Days
Annual totals indicate energy demand for heating and cooling
Heating Degree Days
5,974
Higher = more heating needed
Cooling Degree Days
1,003
Higher = more cooling needed
Warmest Month
July
Coldest Month
January
Humidity & Wind
Monthly averages from hourly observations
| Month | Humidity | Wind (mph) | Clear Sky % | Overcast % |
|---|---|---|---|---|
| January | 73% | 10.5 | 17% | 49% |
| February | 69% | 10.9 | 15% | 47% |
| March | 63% | 11.1 | 15% | 41% |
| April | 60% | 10.5 | 18% | 37% |
| May | 64% | 9.1 | 17% | 28% |
| June | 64% | 8.4 | 18% | 18% |
| July | 66% | 7.8 | 17% | 18% |
| August | 69% | 8.0 | 21% | 18% |
| September | 68% | 9.0 | 22% | 24% |
| October | 68% | 10.4 | 18% | 40% |
| November | 73% | 10.4 | 15% | 48% |
| December | 75% | 10.6 | 14% | 51% |
Nationwide similar cities
Other rankable U.S. places outside IL closest to Chicago on two NOAA annual-normal axes (mean temperature and annual precipitation). Chip rows use distinct link sets.
Closest by average temperature
Nearest out-of-state peers by annual mean temperature (51°F here).
- Bellingham, WA 51°F · 0.0°F off
- Bloomfield, IA 51°F · 0.0°F off
- Burlington, IA 51°F · 0.0°F off
- Denver, CO 51°F · 0.0°F off
Closest by annual precipitation
Nearest out-of-state peers by annual precipitation (37.9" here), excluding temperature-peer places.
- Lockport, NY 37.9" · 0.0" off
- Eldora, IA 37.9" · 0.0" off
- Flatonia, TX 37.9" · 0.0" off
- Marshalltown, IA 37.9" · 0.0" off
Snow and freeze rhythm
When cold and snow define Chicago
heating led · moderate · mid swing
Chicago's energy balance leans toward cold weather: 5,974 annual heating degree days against 1,003 for cooling. Its 50.2°F seasonal range still makes the monthly rows more useful than the annual average alone.
Chicago's frost-free season lasts about 195 days, a middle-length window whose endpoints matter more than the annual average. It describes freeze probability, not year-specific planting conditions.
-
1. Chicago coldest normal
January
Averaging 25°F (-4°C), this month sits below freezing for the month as a whole, not merely overnight.
-
2. Chicago typical freeze period
January through December
The station reports average freezing days from January through December.
-
3. Chicago snow peak
January
Chicago averages 38.4 inches of snow a year, with January the snowiest month on the normals.
Questions about Chicago's climate
How much snow does Chicago get? ▼
How cold does Chicago get in winter? ▼
How much energy does heating and cooling require in Chicago? ▼
Data Sources
Data source: NOAA U.S. Climate Normals v1.0.1 (1991-2020). All figures on this page are from Chicago's primary station: CHICAGO OHARE INTL AP (USW00094846). For informational purposes only.
Place identity: U.S. Census Bureau 2024 Gazetteer places. The 2024 Census Gazetteer identifies the exact name-and-state match as an incorporated place (GEOID 1714000). Match rule for Chicago: exact normalized name + state only, no fuzzy expansion, so nearby differently spelled facilities stay unmatched.
On this page every temperature, precipitation, and derived score for Chicago comes from its primary NOAA station record. No figure on this page is typed in by an editor - each value is rendered from NOAA 1991-2020 U.S. Climate Normals. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 1991–2020 normals.