Today | Weather | Saturday, September 19, 2026
Active Weather Warnings

Weather in Naperville, Illinois

10:02 AM
Now
Stormy Weather
66° F
Feels Like 64°
Precipitation 90 %
Wind 7 mph
UV Index (0 - 11+) 1
Humidity 100 %
Today
Rainy Weather
Day 81°
Night 66°
Precipitation 100 %
Wind 7 mph
UV Index (0 - 11+) 1

Naperville Weather Forecast Updated

19 minutes ago
Last updated on
Weather Forecast History
Last Year's Weather on This Day (September 19, 2025)
Stormy Weather

Day

86°

Night

63°

Wind

5 mph

Precipitation

96 %

Air Quality in Naperville

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

Pollutant Concentrations:

PM2.5 11.32 µg/m³
PM10 11.91 µg/m³
O3 0.030 ppm
NO2 1.7 ppb
SO2 0.6 ppb
CO 0.15 ppm
NH3 0.68 µg/m³
NO 0.63 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)
PM2.511.32 µg/m³
PM1011.91 µg/m³
O358.68 µg/m³
NO23.13 µg/m³
SO21.59 µg/m³
CO173.97 µg/m³
NH30.68 µg/m³
NO0.63 µg/m³

Weather Alerts and Warnings for Naperville

Severe Future Possible

Flood Watch

Flood Watch issued September 19 at 3:39AM CDT until September 19 at 1:00PM CDT by NWS Chicago IL
Sep 19, 4:00 AM Sep 19, 1:00 PM
WHAT: Flash flooding caused by excessive rainfall continues to be
possible.

WHERE: Portions of Illinois, including the following areas,
Central Cook, De Kalb, DuPage, Kane, Kendall, Lake IL, Lee,
Northern Cook, Northern Will and Southern Cook 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. Roads and streets may
be flooded.

ADDITIONAL DETAILS:
- Showers and thunderstorms will produce heavy rain this morning
which may cause localized flash flooding. Additional showers and
thunderstorms may produce heavy rain and localized flash flooding
tonight when another flood watch for flash flooding may be
needed.
- 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 19, 9:43 AM Source: NWS Alert