UV Index in Union, United States

Last updated: May 3, 2025

In Union, United States, staying informed about the UV Index is crucial for protecting your skin against harmful ultraviolet radiation. Understanding the varying UV levels throughout the day allows residents to take proactive measures to prevent sunburn and promote overall skin health. With a humid subtropical climate (Cfa), Union experiences significant UV exposure, especially during peak hours from 11 AM to 3 PM, where the index can soar as high as 10. Being mindful of these factors not only enhances your outdoor enjoyment but also safeguards your well-being against long-term skin damage.

Hourly UV Index in Union

The UV Index data reveals a striking progression throughout the day. Early risers at 07:00 and 08:00 will experience a low UV Index of 1, making it a safe window for outdoor activities. However, as the day unfolds, 9:00 sees a jump to 3, which hints at increasing sun intensity. The real peak occurs between 12:00 and 14:00, where the UV Index hits its maximum at 10—a critical period for sun exposure, urging caution for those outdoors. As the afternoon transitions to evening, the index gradually drops, settling back to a more manageable 1 by 19:00. This data highlights the importance of sun safety during the midday hours, as the sun's rays can be particularly harsh.

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	4	moderate	30 min
11:00	7	high	25 min
12:00	9	very high	15 min
13:00	10	very high	15 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

Throughout the year, the UV Index exhibits notable seasonal changes, with the highest levels occurring from April to September. During this peak period, particularly in May, June, and July, the UV Index reaches 10—categorized as very high, necessitating vigilant sun protection measures. Visitors and residents should be particularly cautious in these months, as the burn time drops to just 15 minutes. March marks the transition to high exposure, with an index of 6, while October and November see a decline to moderate levels and longer burn times of 25 to 30 minutes. To safeguard against UV-related health risks, it is essential to wear sunscreen, hats, and protective clothing, especially during the high-risk months of April to September.

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
Union	3	5	6	9	10	10	10	9	8	6	4	3
Los Angeles UVI	4	6	8	9	10	11	11	10	10	7	5	4
Houston UVI	5	8	9	11	11	12	12	11	10	9	7	5