UV Index in Princeton, United States

Last updated: May 3, 2025

Understanding the UV Index in Princeton, United States, is essential for protecting your skin and maintaining your overall health. With peak UV levels reaching up to 10 during the midday hours, awareness of changing UV conditions can help prevent sunburn and long-term skin damage. Princeton's humid subtropical climate (Cfa) contributes to increased UV exposure, especially in summer months. Stay informed about UV Index levels so you can enjoy the outdoors while keeping your skin safe!

Hourly UV Index in Princeton

As the day unfolds, the UV Index reveals a dynamic pattern that encourages cautious sun exposure. Starting gently at 1 at 07:00, the intensity slowly climbs to a moderate 2 by 08:00. However, the real ascent begins at 09:00, when the index reaches 4. The peak occurs between 12:00 and 13:00, with an impressive 10, indicating a high risk of harm from unprotected sun exposure. Following this peak, the UV levels gradually decline, dipping to 9 at 14:00 and then decreasing further to 3 by 17:00. As evening approaches, the UV Index wanes to 1 by 18:00 and 19:00, emphasizing the importance of smart sun safety, especially during the midday hours when the sun's rays are most potent.

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	2	low	45 min
09:00	4	moderate	30 min
10:00	7	high	25 min
11:00	9	very high	15 min
12:00	10	very high	15 min
13:00	10	very high	15 min
14:00	9	very high	15 min
15:00	7	high	25 min
16:00	5	moderate	30 min
17:00	3	moderate	30 min
18:00	1	low	45 min
19:00	1	low	45 min

Monthly UV Index Trends in Princeton

The UV Index exhibits significant seasonal changes, with the highest levels occurring from March to September. Visitors and residents should be particularly cautious during the high-risk months of April, May, June, July, August, and September, when UV exposure reaches very high to extreme levels, with burn times as low as 10 to 15 minutes. In contrast, January, February, November, and December experience moderate UV levels, allowing for longer safe exposure times of 30 minutes. To minimize the risk of skin damage, it is advised that individuals wear appropriate sun protection, such as sunscreen, hats, and protective clothing, especially during peak UV hours from 10 AM to 4 PM.

Monthly Maximum UV Index for Princeton, United States

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in Princeton. 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 Princeton, 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 Princeton UV Index with Other United States Cities

The table above highlights how UV exposure in Princeton 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.

Princeton'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
Princeton	3	5	7	10	10	11	10	9	9	7	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