Today | Weather | Sunday, September 20, 2026
Active Weather Warnings

Weather in Chicago, Illinois

09:37 AM
Now
Rainy Weather
68° F
Feels Like 63°
Precipitation 68 %
Wind 17 mph
UV Index (0 - 11+) 1
Humidity 88 %
Today
Rainy Weather
Day 68°
Night 61°
Precipitation 100 %
Wind 18 mph
UV Index (0 - 11+) 1

Chicago Weather Forecast Updated

4 minutes ago
Last updated on
Weather Forecast History
Last Year's Weather on This Day (September 20, 2025)
Stormy Weather

Day

81°

Night

66°

Wind

6 mph

Precipitation

88 %

Air Quality in Chicago

NOW
39 AQI
Good air quality Dominant pollutant: PM2.5

Pollutant Concentrations:

PM2.5 9.47 µg/m³
PM10 9.61 µg/m³
O3 0.024 ppm
NO2 2.3 ppb
SO2 0.3 ppb
CO 0.16 ppm
NH3 0.59 µg/m³
NO 0.09 µg/m³
PM2.5 – Fine particles <2.5μm
PM10 – Inhalable particles <10μm
O3 – Ozone
NO2 – Nitrogen dioxide
SO2 – Sulfur dioxide
CO – Carbon monoxide
NH3 – Ammonia
NO – Nitric oxide

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

Show raw pollutant concentrations (µg/m³)
PM2.59.47 µg/m³
PM109.61 µg/m³
O347.86 µg/m³
NO24.41 µg/m³
SO20.69 µg/m³
CO178.07 µg/m³
NH30.59 µg/m³
NO0.09 µg/m³

Weather Alerts and Warnings for Chicago

Severe Future Possible

Flood Watch

Flood Watch issued September 20 at 1:33AM CDT until September 20 at 1:00PM CDT by NWS Chicago IL
Sep 20, 1:33 AM Sep 20, 1:00 PM
WHAT: Flash flooding caused by excessive rainfall continues to be
possible.

WHERE: Portions of Illinois, including the following areas, Boone,
Central Cook, De Kalb, DuPage, Eastern Will, Grundy, Kane,
Kankakee, Kendall, La Salle, Lake IL, Lee, McHenry, Northern Cook,
Northern Will, Ogle, Southern Cook, Southern Will and Winnebago and
northwest Indiana, including the following areas, Lake IN and
Porter.

WHEN: Until 1 PM CDT this afternoon.

IMPACTS: Creeks and streams may rise out of their banks. Flooding
may occur in poor drainage and urban areas. Underpasses may be
flooded. Roads and streets may be flooded. Basement flooding may
occur.

ADDITIONAL DETAILS:
- Periods of showers and thunderstorms are expected through midday.
Swaths of torrential rain with 2 inch per hour rainfall rates, or
higher are likely to occur within the watch area and may result
in areas of flash flooding and cause rapid rises on area rivers,
creeks, and streams.
- http://www.weather.gov/safety/flood
+ Read More
A Flood Watch for flash flooding means rapid-onset flooding is possible, but not yet certain, based upon the latest forecasts. Flash flooding is a dangerous situation. Persons with interests along area rivers, creeks, and other waterways should monitor the latest forecasts and be prepared to take action should flooding develop.
Updated: Sep 20, 9:32 AM Source: NWS Alert
Moderate Expected Likely

Beach Hazards Statement

Beach Hazards Statement issued September 20 at 3:17AM CDT until September 22 at 7:00PM CDT by NWS Chicago IL
Sep 20, 7:00 AM Sep 22, 7:00 PM
WHAT: High wave action and dangerous currents expected at Lake
Michigan beaches. Waves 7 to 10 feet expected.

WHERE: Lake IL, Northern Cook and Central Cook Counties.

WHEN: From 7 AM CDT this morning through Tuesday evening.

IMPACTS: Swimming conditions will be life threatening,
especially for inexperienced swimmers.
+ Read More
Remain out of the water to avoid dangerous swimming conditions and do not venture out onto piers, jetties, breakwalls, or other shoreline structures.
Updated: Sep 20, 9:32 AM Source: NWS Alert
Minor Expected Likely

Flood Advisory

Flood Advisory issued September 20 at 7:04AM CDT until September 20 at 10:00AM CDT by NWS Chicago IL
Sep 20, 7:04 AM Sep 20, 10:00 AM
WHAT: Flooding caused by excessive rainfall continues.

WHERE: East Central Cook County in northeastern Illinois...
Southern DuPage County in northeastern Illinois...
Southern Kane County in northeastern Illinois...
Northern Kendall County in northeastern Illinois...
Northwestern Will County in northeastern Illinois...

WHEN: Until 1000 AM CDT.

IMPACTS: Creeks and streams may rise out of their banks.

ADDITIONAL DETAILS:
- At 701 AM CDT, Doppler radar and automated rain gauges indicated
heavy rain due to thunderstorms earlier this morning. Minor
flooding is ongoing in the advisory area. Up to 2 inches of rain
have fallen.
- Though heavy rain has ended, creeks and streams may continue to
rise and will remain elevated this morning.
- Some locations that will experience flooding include...
South Side of Chicago, Aurora, Naperville, Cicero, Bolingbrook,
Oak Lawn, Berwyn, Wheaton, Downers Grove, Lombard, Woodridge,
Oswego, Midway Airport, South Lawndale, Chicago Lawn, Englewood,
Bridgeport, Roseland, Chicago Loop, South Shore and Burbank.
- http://www.weather.gov/safety/flood
+ Read More
A Flood Advisory means minor flooding along waterways and other poor drainage areas is imminent or may already be occurring. Persons in the advisory area should use caution and avoid flood waters. Turn around, don't drown when encountering flooded roads. Most flood deaths occur in vehicles.
Updated: Sep 20, 9:32 AM Source: NWS Alert