Chicago, Illinois Weather
Day 93 of summer. Read today’s microseason across nine climate regions →
Chicago weather forecast — hour by hour, 7-day outlook, NOAA radar
Conditions updated 4:41 AM CDT · Open-Meteo
- TodaySep 21Overcast17%—64°59°—
- TuesdaySep 22Overcast——60°55°-4°
- WednesdaySep 23Overcast——63°59°+3°
- ThursdaySep 24Overcast——64°61°+1°
- FridaySep 25Overcast——67°59°+3°
- SaturdaySep 26Overcast——63°59°-4°
- SundaySep 27Overcast13%—69°57°+6°
Air quality now AQI 30 · Good
AQI 30 (Good), driven by Ozone. AQI flat over the last 6 hours (within ±3 points). Ozone at AQI 34. Overcast through the UV peak window (cloud cover ~85%) — afternoon ozone should stay flat.
OK No precautions needed for the general population; unusually sensitive individuals may consider limiting prolonged outdoor exertion.
What's driving it
Ozone × UV × Sky
Ozone at AQI 34. Overcast through the UV peak window (cloud cover ~85%) — afternoon ozone should stay flat.
- Present
- AQI 34
- UV peak
- 3.3 at 1 PM
- Sky at peak
- overcast
- Projected peak
- AQI 8
Trends
Seven days of AQI and PM2.5.
Hourly air-quality data from the Copernicus Atmosphere Monitoring Service, charted across the past and next several days. Dashed lines mark the AQI breakpoints at 50 (Good → Moderate) and 100 (Moderate → Unhealthy for Sensitive Groups).
September dries up ditches or breaks down bridges.
- Moonrise
- 4:29 PM
- Moonset
- 1:05 AM
- In sign
- ♑︎ Capricorn
Chicago at a glance
- Today vs. normal: Today averages 62°F (high 64°F, low 59°F), 3°F below the 65°F normal for Sep 21
- Last frost: April 10 (1991–2020 median, NOAA station 7 km away)
- Microseason: Sep 21–25
- Planting calendar: September — plant garlic (overwinter); harvest tomatoes, peppers, beans, summer squash, winter squash
15-Day Forecast — Chicago
- Mon64°59°17%
- Tue60°55°5%
- Wed63°59°4%
- Thu64°61°1%
- Fri67°59°1%
- Sat63°59°4%
- Sun69°57°13%
- Mon72°58°10%
- Tue73°59°23%
- Wed65°57°25%
- Thu70°57°13%
- Fri70°62°16%
- Sat68°64°16%
- Sun83°64°16%
- Mon76°62°23%
Forecast data from Open-Meteo (CC BY 4.0).
Live wind & temperature near Chicago
Interactive wind and temperature map centered on Chicago — it loads in your browser. Open the full weather map.
Right now in the garden
Fall planting + final harvests
As of September 21, the season's first frost (typically November 5) is approaching. Pick what frost-tender plants still carry before the next cold front. This city's planting calendar for September: plant garlic (overwinter); harvest tomatoes, peppers, beans, summer squash, and winter squash.
Sun & seasons in Chicago
Chicago sits in Cook County, where the year’s longest day runs 15h 13m of daylight and its shortest just 9h 8m — a swing of +6h 6m between the June and December solstices. Clocks spring forward on Sunday, March 8, 2026 and fall back on Sunday, November 1, 2026.
Chicago is the state’s largest city. The nearest town Chicago tracks is Willow Springs, roughly 13 miles to the SW.
Air quality in Chicago
Air quality in Chicago’s county has trended cleaner since 2020; its cleanest year on record was 2025 (median AQI 53). See the full air-quality history for Chicago.
Planting calendar
| Month | Plant | Harvest |
|---|---|---|
| March | lettuce, peas, spinach, radishes | — |
| April | lettuce, peas, spinach, radishes | spinach, radishes |
| May | tomatoes, peppers, beans, squash | lettuce, peas, spinach, radishes |
| June | tomatoes, peppers, beans, squash | lettuce, peas, spinach, garlic |
| July | tomatoes, peppers, beans, squash | peas, beans, summer squash, garlic |
| August | beans, squash, fall brassicas, carrots | tomatoes, peppers, beans, summer squash |
| September | garlic (overwinter) | tomatoes, peppers, beans, summer squash, winter squash |
| October | garlic (overwinter) | tomatoes, peppers, beans, summer squash, winter squash, fall brassicas, carrots |
| November | — | fall brassicas, carrots |
A year in weather
Chicago peaks at about 76°F in July and bottoms near 24°F in January; May brings the heaviest rain (4.2 inches) and January the least (2.0 inches).
| Month | Mean temp | Precip |
|---|---|---|
| January | 24° | 2.0″ |
| February | 27° | 2.1″ |
| March | 37° | 3.0″ |
| April | 50° | 3.8″ |
| May | 59° | 4.2″ |
| June | 70° | 4.0″ |
| July | 76° | 2.9″ |
| August | 75° | 3.0″ |
| September | 68° | 3.1″ |
| October | 55° | 3.0″ |
| November | 40° | 3.2″ |
| December | 28° | 2.5″ |
Regional context
Similar climates Cicero, IL, Stickney, IL, Forest View, IL
Chicago swings from 24°F in January to 76°F in July (53°F) per modelled 1991-2020 normals (EC_Earth3P_HR model via Open-Meteo); precipitation in Chicago runs about 36.8 inches.
No season owns Chicago's rain: May reaches 4.2 inches and January keeps 2.0 inches, an even spread through Chicago's year. That lines Chicago up with places like Cicero, IL, Stickney, IL and Forest View, IL, fed by overlapping storm tracks.
Around April 10, Chicago sheds its freezing nights — kale, peas, spinach, and parsnips go into Chicago's beds. Chicago's heat-lovers — tomatoes, peppers, squash — hold off until Chicago's frost risk clears, 10-14 days on. The season ends by November 5 in Chicago, once hard frosts set back in. That date is a median: Chicago freezes sooner in half of years.
Similar climates: Cicero, IL, Stickney, IL, Forest View, IL, Berwyn, IL, Oak Park, IL.
Frequently asked
- When does it freeze in Chicago?
- Chicago's last spring frost lands near April 10, and in Chicago the first fall frost follows around November 5.
- What is the rainy season in Chicago?
- Rainfall in Chicago peaks in May near 4.2 inches, out of about 37 inches annually.
- What is the warmest month in Chicago?
- On average July tops the year in Chicago at about 76°F.
- What is the coldest month in Chicago?
- The coldest stretch in Chicago falls in January, around 24°F on average.
- When can I start a vegetable garden in Chicago?
- Around April 10, start frost-hardy crops in Chicago; tomatoes and basil belong a fortnight later.
- What hardiness zone is Chicago?
- Since January in Chicago averages 24°F, Chicago's USDA zone follows that floor — confirm it by ZIP.
- What is the 10-day forecast for Chicago?
- Chicago's extended outlook — daily high and low temperatures and precipitation chances for each upcoming day — is in the daily forecast above.
- Will it rain this week in Chicago?
- See this week's day-by-day rain chances for Chicago in the daily forecast above, and the next 24 hours in the hourly chart.
- What is the weather like right now in Chicago?
- Current conditions for Chicago and the next 24 hours — temperature, precipitation chance, and wind by the hour — are in the hourly forecast chart above.
- How often is the Chicago forecast updated?
- The Chicago forecast on this page is built from Open-Meteo weather-model data and refreshes regularly through the day.
- When are sunrise and sunset in Chicago?
- Today's sunrise and sunset times for Chicago are in the Almanac section above, along with civil dawn, civil dusk, and day length. Day length is longest near the summer solstice and shortest near the winter solstice.
- How accurate is the weather forecast for Chicago?
- The next few days in Chicago's forecast are the most reliable; accuracy declines beyond about a week as weather-model uncertainty grows.
Chicago sits at 41.8°N; its climate zone is warm-summer humid continental (Köppen approximation).
ZIP codes in Chicago
- 60018
- 60106
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