United States
UV Index in Illinois — Current UV Levels
Check the current UV index for 1 cities in Illinois. Select a city below for real-time UV data, hourly forecasts, and sun protection advice.
UV Index by City in Illinois
Sun Safety in Illinois
UV levels in Illinois vary by season, altitude, and proximity to water. The WHO recommends sun protection whenever UV reaches 3 or higher. Apply SPF 30+ before outdoor activities and reapply every 2 hours.
UV Index in Illinois: What to Know
Illinois has moderate-to-high UV in summer, peaking around the solstice. Chicago and the rest of the state see their strongest UV in June and July.
Across Illinois, the UV index peaks in the four hours around solar noon (roughly noon to 3 PM local time). The World Health Organization recommends sun protection whenever the UV index reaches 3 or higher: apply broad-spectrum SPF 30 at UV 3–5, SPF 50 at UV 6–7, and SPF 50+ with reapplication every two hours at UV 8 and above. Check the live, hour-by-hour UV index for Chicago on the city pages above before heading outdoors.
Common Questions About UV in Illinois
When is the UV index highest in Illinois?
UV in Illinois is strongest between noon and 3 PM local time, and highest in the summer months when the sun sits highest in the sky. Check the hourly chart for Chicago above to see today's exact peak.
Do I need sunscreen in Illinois?
Yes — whenever the UV index reaches 3 or higher, which in Illinois covers most of the daytime hours from spring through fall. Even on cloudy days, up to 80% of UV can reach the ground.
How accurate is this UV data for Illinois?
Our UV index for Illinois comes from Open-Meteo, which aggregates national weather-service models, and updates every 15 minutes. Levels follow the official WHO global solar UV index scale.