Today | Weather | Tuesday, September 1, 2026
Active Weather Warnings

Weather in Decatur, Illinois

10:25 AM
Now
Sunny Weather
84° F
Feels Like 91°
Precipitation 0 %
Wind 9 mph
UV Index (0 - 11+) 4
Humidity 59 %
Today
Hot Day
Day 99°
Night 73°
Precipitation 1 %
Wind 8 mph
UV Index (0 - 11+) 7

Decatur Weather Forecast Updated

26 minutes ago
Last updated on

Air Quality in Decatur

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

Pollutant Concentrations:

PM2.5 8.48 µg/m³
PM10 9.36 µg/m³
O3 0.029 ppm
NO2 2.5 ppb
SO2 1 ppb
CO 0.13 ppm
NH3 1.14 µg/m³
NO 1.25 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)
PM2.58.48 µg/m³
PM109.36 µg/m³
O357.33 µg/m³
NO24.64 µg/m³
SO22.66 µg/m³
CO145.07 µg/m³
NH31.14 µg/m³
NO1.25 µg/m³

Weather Alerts and Warnings for Decatur

Moderate Expected Likely

Heat Advisory

Heat Advisory issued September 1 at 2:48AM CDT until September 3 at 7:00PM CDT by NWS Lincoln IL
Sep 1, 2:48 AM Sep 3, 7:00 PM
WHAT: Afternoon Heat index values up to 105, only falling into the
mid to upper 70s at night.

WHERE: Portions of central, east central, southeast, and west
central Illinois.

WHEN: Until 7 PM CDT Thursday.

IMPACTS: Hot temperatures and high humidity may cause heat
illnesses.
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Take extra precautions when outside. Wear lightweight and loose fitting clothing. Try to limit strenuous activities to early morning or evening. Take action when you see symptoms of heat exhaustion and heat stroke.
Updated: Sep 1, 9:58 AM Source: NWS Alert