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Today | Weather | Monday, August 18, 2025
Severe Thunderstorm Watch (Issued when severe thunderstorms with damaging winds or large hail are possible. Stay alert for warnings.) Beach Hazards Statement (Potential hazards at beaches, such as dangerous currents, high surf, or unexpected waves.)

Weather in Chicago, Illinois

01:59 PM
Now
Cloudy WeatherCloudy weather, overcast skies with clouds.
82° F
Feels Like 88°
Precipitation 34 %
Wind 8 mph
UV Index (0 - 11+) 11
Humidity 66 %
Today
Sunny with a Chance of ThunderstormsSunny weather with a possibility of isolated thunderstorms developing later in the day.
Day 84°
Night 73°
Precipitation 87 %
Wind 9 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.

Chicago Weather Forecast Updated

51 minutes ago
Last updated on

Weather Forecast History

Last Year's Weather on This Day (August 18, 2024)

Partly Sunny with ShowersPartly sunny weather with scattered clouds and occasional rain showers.

Day

79°

Night

68°

Wind

16 mph

UV Index

4

Precipitation

40

Air quality in Chicago

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

Pollutant Concentrations:

PM2.5 11.32 µg/m³
PM10 11.55 µg/m³
O₃ 63.04 ppb
NO₂ 2.80 ppb
SO₂ 1.38 ppb
CO 203.43 ppb
PM2.5 – Fine particles <2.5μm
PM10 – Inhalable particles <10μm
O3 – Ozone
NO2 – Nitrogen dioxide
SO2 – Sulfur dioxide
CO – Carbon monoxide

Health Recommendations:

With this level of air quality, you have no limitations. Enjoy the outdoors

View Hourly Air Quality Forecast