Today | Weather | Thursday, May 21, 2026

Weather in Joliet, Illinois

10:19 AM
Now
Cloudy Weather
57° F
Feels Like 55°
Precipitation 0 %
Wind 12 mph
UV Index (0 - 11+) 3
Humidity 75 %
Today
Cloudy Weather
Day 66°
Night 54°
Precipitation 4 %
Wind 13 mph
UV Index (0 - 11+) 8

Warning: High UV Index Today: 8

High risk of harm from unprotected sun exposure. Take precautions: wear a hat, sunglasses, and apply sunscreen regularly if you’ll be outdoors for extended periods.

Joliet Weather Forecast Updated

Last updated on
Weather Forecast History
Last Year's Weather on This Day (May 21, 2025)
Rainy Weather

Day

54°

Night

48°

Wind

11 mph

UV Index

2

Precipitation

84 %

Air Quality in Joliet

NOW
26 AQI
Good air quality Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 5.56 µg/m³
PM10 6.24 µg/m³
O3 0.028 ppm
NO2 3.2 ppb
SO2 0.8 ppb
CO 0.13 ppm
NH3 6.2 µg/m³
NO 1.22 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)
PM2.55.56 µg/m³
PM106.24 µg/m³
O355.43 µg/m³
NO26 µg/m³
SO22 µg/m³
CO152.47 µg/m³
NH36.2 µg/m³
NO1.22 µg/m³