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UV Index in Chicago Today
November 12, 2026 · Chicago, USA
2,720,546 people
See today's UV index in Chicago hour by hour below. The UV index shows how strong the sun's ultraviolet radiation is — the higher the number, the faster skin can burn. Values are calculated for Chicago's coordinates and updated daily.
No protection needed
Hour by hour
Clouds cut the peak by ~53%Clear sky
Remember today
- Safe to be outside unprotected
Daylight: sunrise 06:37 – sunset 16:34
Tomorrow: UV 1 at its peak around 11:00
The UV index in Chicago peaks at 1 (low) around 12:00 today. The index stays below 3 all day, so no particular sun protection is needed. Cloud cover is damping the peak by roughly 53% compared with a clear sky. Tomorrow the index is forecast to peak at 1 around 11:00.
UV index in Chicago hour by hour
| Time | UV index | Level |
|---|---|---|
| 06:00 | 0 | Low |
| 07:00 | 0.1 | Low |
| 08:00 | 0.2 | Low |
| 09:00 | 0.3 | Low |
| 10:00 | 0.5 | Low |
| 11:00 | 0.8 | Low |
| 12:00 | 0.9 | Low |
| 13:00 | 0.6 | Low |
| 14:00 | 0.4 | Low |
| 15:00 | 0.2 | Low |
| 16:00 | 0 | Low |
| 17:00 | 0 | Low |
UV index in Chicago
Chicago lies at 42°N. The midday sun reaches 30.4° above the horizon in Chicago today, against a yearly ceiling of 71.6°. Elevation is what sets the ceiling for UV, and over Chicago it is high enough for the index to reach very high values through the summer months.
What is the UV index?
The UV index is an international scale describing the strength of the sun's ultraviolet radiation at ground level. It starts at 0 and is effectively open-ended — at mid-latitudes it rarely exceeds 8, while in the tropics and high in the mountains it can pass 11. The higher the number, the less time it takes to get sunburnt.
The UV index depends mainly on how high the sun is in the sky. That is why it peaks around solar noon and is greatest in summer near the longest day of the year. Clouds, ozone, altitude and reflection from snow or water also affect the value.
The WHO UV scale
| UV index | Level | Recommendation |
|---|---|---|
| 0–2 | Low | No special protection needed. |
| 3–5 | Moderate | Use sunscreen (SPF 30+), seek shade around midday. |
| 6–7 | High | Sunscreen, hat and sunglasses. Avoid the sun 12:00–15:00. |
| 8–10 | Very high | Extra protection. Limit midday sun exposure. |
| 11+ | Extreme | Avoid the sun at midday. Full protection required. |
See also sunrise, sunset and daylight hours in Chicago.