UV Index Today in Chicago, Illinois

Current UV

Today's Max

Hourly UV Forecast

low moderate high very high extreme

Surface Type

Reflective surfaces increase your UV exposure — snow reflects up to 90%, sand about 20%.

Safe Exposure Time

Estimated burn times based on the Fitzpatrick scale for skin color and today's maximum UV index of . Tap your skin type:

Very fair skin, always burns, never tans

Time until burn

With SPF 15*

With SPF 30*

*Assumes proper application of broad-spectrum sunscreen with reapplication every 2 hours. Estimates follow WHO guidance and satellite-derived data — see how our data works.

Sun Times

Dawn

Sunrise

Solar Noon

Sunset

Dusk

Day Length

Morning Golden Hour Ends

Evening Golden Hour

Important Safety Information

General Guidelines

These exposure times are estimates based on scientific research and should be used as general guidelines only. Individual responses to UV exposure may vary.

Affecting Factors

UV exposure is affected by: time of day, season, altitude, cloud cover, reflection from surfaces, and individual skin sensitivity.

Protection Tips

Seek shade during peak UV hours (10 AM - 4 PM), wear protective clothing, use broad-spectrum sunscreen, and monitor the UV index regularly.

Medical Advice

Consult a healthcare provider for personalized sun protection advice, especially if you have a history of skin conditions or take medications that increase sun sensitivity.

Chicago's UV Climate

Chicago, located on the shores of Lake Michigan, experiences a humid continental climate with moderate to high UV exposure during the summer months. The city's northern latitude and frequent cloud cover reduce UV intensity compared to southern cities, but clear summer days can still bring high UV levels. Residents and visitors should use sun protection during outdoor activities, especially near water where reflection increases exposure.

Average Annual UV Index

6.2

Peak UV Season

May - September

Sunny Days per Year

189

Typical UV Index by Season in Chicago

Season	Typical Midday UV	Protection Needed
Summer	High to Very High (7-9)	SPF 30+, hat, sunglasses; shade from 10 AM – 4 PM
Spring & Fall	Moderate (4-6)	SPF 30+ for extended time outdoors
Winter	Low (1-2)	Sunscreen for long midday exposure; more on snow

UV Index in Nearby Cities

Practical Tips for Outdoor Activities

Make the most of outdoor activities while staying safe in Cook County:

Check UV index and weather radar before planning outdoor activities
Schedule outdoor activities during low UV hours
Use appropriate sun protection based on UV levels
Stay hydrated during outdoor activities
Take regular breaks in shaded areas
Monitor weather conditions for changes
Be prepared for sudden weather changes
Know the signs of heat-related illness
Wear a hat and protective clothing
Check visibility conditions before outdoor plans
Stay alert to weather alerts and warnings

UV and Weather in Cook County

Learn about Cook County's unique climate patterns, UV radiation levels, and how they affect your daily life. Enter your zip code for location-specific weather radar data and UV forecasts to help you make informed decisions about outdoor activities and sun protection.

Climate and UV Patterns

Chicago's climate features cold winters and warm, humid summers. UV index values are highest from late spring through early fall, with peak values reaching 8-9 on clear days. The lake effect can moderate temperatures but does not significantly reduce UV exposure. Cloud cover is common, but when skies are clear, UV radiation can be intense.

UV Index and Health Impact

Understanding UV radiation levels is crucial for protecting your health. Typical clear-day UV index values in Chicago through the year:

Summer: High to Very High (7-9)
Spring/Fall: Moderate (4-6)
Winter: Low (1-2)
Peak UV hours: 10 AM - 4 PM
Cloud cover can reduce UV by 20-40%, but does not eliminate it
Clear skies bring maximum UV exposure

Local Weather Patterns

Chicago's weather is highly variable, with frequent changes in cloud cover and temperature. Summer brings the highest UV exposure, especially during midday hours. The presence of Lake Michigan can increase UV reflection, making sun protection important for beachgoers and boaters. Winter UV levels are low but not negligible, especially on sunny, snowy days.

Frequently Asked Questions About UV in Chicago

What is the UV index in Chicago today?

The live UV index for Chicago, IL is shown at the top of this page and updates throughout the day, along with today's maximum and an hourly forecast.

When is the sun strongest in Chicago?

UV radiation is strongest between 10 AM and 4 PM. Chicago's peak UV season runs May - September, when the midday index typically reaches High to Very High (7-9).

How high does the UV index get in Chicago?

Summer days in Chicago typically reach High to Very High (7-9). Spring and fall usually bring Moderate (4-6), while winter values are typically Low (1-2).

Do I need sunscreen in Chicago during winter?

Winter UV in Chicago is usually low, so sunburn risk is limited on typical days. Sunscreen is still wise during midday hours or around reflective snow.

How sunny is Chicago compared to other cities?

Chicago averages about 189 sunny days per year with an average annual UV index around 6.2.