Today | Weather | Monday, June 29, 2026

Active Weather Warnings

Heat Advisory

Weather in Decatur, Illinois

08:11 PM

Now

88° F

Feels Like 91°

Precipitation 0 %

Wind 10 mph

UV Index (0 - 11+) 0

Humidity 65 %

Today

Day 91°

Night 75°

Precipitation 21 %

Wind 12 mph

UV Index (0 - 11+) 11

Warning: Extreme UV Index Today: 11

Overexposure to the sun's harmful UV rays can cause sunburn and increase the risk of developing skin cancer, including melanoma. Protect yourself by wearing clothing that covers your skin, sunglasses, and a hat. Apply a broad-spectrum sunscreen with an SPF of 30 or higher every two hours, even on cloudy days. Minimize direct sun exposure during peak hours (10 AM to 4 PM) to reduce the risk.

Decatur Weather Forecast Updated

Last updated on June 29, 2026 at 6:42 PM

Air Quality in Decatur

NOW

27 AQI

Good air quality Dominant pollutant: O₃

Pollutant Concentrations:

PM_2.5 5.56 µg/m³

PM₁₀ 7.82 µg/m³

O₃ 0.029 ppm

NO₂ 1.5 ppb

SO₂ 0.8 ppb

CO 0.11 ppm

NH₃ 0.92 µg/m³

NO 0.11 µg/m³

PM_2.5 – 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)

PM_2.5 – 5.56 µg/m³

PM₁₀ – 7.82 µg/m³

O₃ – 57.44 µg/m³

NO₂ – 2.88 µg/m³

SO₂ – 2.17 µg/m³

CO – 122.52 µg/m³

NH₃ – 0.92 µg/m³

NO – 0.11 µg/m³

View Hourly Air Quality Forecast

Weather Alerts and Warnings for Decatur

Moderate Expected Likely

Heat Advisory

Heat Advisory issued June 29 at 1:45PM CDT until July 3 at 12:00AM CDT by NWS Lincoln IL

Jun 29, 1:45 PM → Jul 3, 12:00 AM

WHAT: Heat index values 105 to 110 expected.

WHERE: All of central and southeast Illinois.

WHEN: Until midnight CDT Thursday Night.

IMPACTS: Hot temperatures and high humidity may cause heat
illnesses.

ADDITIONAL DETAILS: The cumulative effects of this prolonged heat
will pose a serious public health risk, especially for individuals
outdoors or without adequate air conditioning.

+ Read More

Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors. Do not leave young children and pets in unattended vehicles. Car interiors will reach lethal temperatures in a matter of minutes.

Updated: Jun 29, 6:42 PM Source: NWS Alert