UV Index in Union, United States

Last updated: July 2, 2025

In Union, United States, understanding the UV Index is critical for maintaining skin health and preventing sunburn. With a Cfa climate, residents and visitors experience a range of UV exposures that peak in the early afternoon. As UV levels can soar to 11—which poses a high risk of harm—knowing when to seek shade or apply sunscreen can make a significant difference in long-term skin health. By staying informed about the UV Index, you can protect yourself and your loved ones from the harmful effects of sun exposure throughout the year.

Hourly UV Index in Union

Throughout the day, the UV Index peaks dramatically, starting at a mild 1 in the early morning at 7:00 AM and 8:00 AM. As the sun climbs higher, 9:00 AM sees a moderate increase to 3, but it’s not until 10:00 AM that the UV Index hits 5, signaling a need for some sun protection. The intensity truly soars at 11:00 AM, reaching 7, and by 12:00 PM it escalates to a striking 9, before soaring to its maximum of 11 at 1:00 PM. After the zenith, the index gradually recedes to 10 at 2:00 PM, and then descends slowly: 9 at 3:00 PM, 7 at 4:00 PM, and down to 4 by 5:00 PM. The evening brings relief, as the UV Index dips to 2 at 6:00 PM and finally settles back to 1 as the sun sets at 7:00 PM. Ensure to stay protected during those peak hours!

Average solar exposure data for the current time of the year. Actual values may vary and depend on many factors, such as cloud cover, vegetation cover, surface type, etc.
Time	UVI	Category	Time to Burn
07:00	1	low	45 min
08:00	1	low	45 min
09:00	3	moderate	30 min
10:00	5	moderate	30 min
11:00	7	high	25 min
12:00	9	very high	15 min
13:00	11	extreme	10 min
14:00	10	very high	15 min
15:00	9	very high	15 min
16:00	7	high	25 min
17:00	4	moderate	30 min
18:00	2	low	45 min
19:00	1	low	45 min

Monthly UV Index Trends in Union

As the year progresses, UV radiation levels vary significantly, with the most intense exposure typically occurring from March through August. During this period, the UV Index reaches its peak levels, particularly in May, June, and July, where it is marked as extreme (Index of 11) and the burn time is as short as 10 minutes. Visitors and residents should take extra precautions during these high-risk months to protect their skin, including wearing protective clothing, using broad-spectrum sunscreen, and seeking shade during peak sunlight hours. As the year transitions into the fall months, UV levels decrease, dropping to moderate by December, providing some relief from the risks associated with UV exposure.

Monthly Maximum UV Index for Union, United States

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in Union. It measures the strength of ultraviolet radiation from the sun and helps assess the risk of sunburn and UV-related health issues.

Data source: Statistical UV Index data for Union, based on information from the Copernicus Climate Change Service.

UV Risk Categories

Extreme (11+): Avoid the sun, stay in shade.
Very High (8-10): Limit sun exposure.
High (6-7): Use SPF 30+ and protective clothing.
Moderate (3-5): Midday shade recommended.
Low (0-2): No protection needed.

Compare Union UV Index with Other United States Cities

The table above highlights how UV exposure in Union compares to other major locations across United States. This comparison helps travelers and residents better understand regional sun intensity and plan outdoor activities with sun safety in mind.

Union's solar exposure compared to other cities in United States. Generated using Copernicus Atmosphere Monitoring Service information.
	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Chicago UVI	3	4	6	8	9	10	10	9	8	6	4	2
Brooklyn UVI	3	5	6	8	10	10	9	9	8	6	4	2
New York City UVI	3	5	6	8	10	10	9	9	8	6	4	2
Los Angeles UVI	4	6	8	9	10	11	11	10	10	7	5	4
Union	4	6	8	10	11	11	11	10	9	8	6	3
Houston UVI	5	8	9	11	11	12	12	11	10	9	7	5