UV Index in Princeton, United States

Last updated: June 2, 2025

Understanding the UV Index is crucial for residents of Princeton, United States, where the combination of a humid continental climate (Dfa) and varying sun exposure can escalate skin health risks. Being aware of UV levels helps prevent sunburn and long-term skin damage, as the index peaks at 11 around midday, indicating a very high risk of harm from unprotected sun exposure. With typical summer days bringing strong sun, mastering UV safety is essential for enjoying outdoor activities while safeguarding your skin. Stay informed and take proactive steps to protect yourself from harmful UV rays throughout the day in Princeton!

Hourly UV Index in Princeton

The UV Index for today shows a dramatic rise as the sun ascends into the sky. Starting at a mild 1 by 07:00, the index gradually builds, reaching 3 by 09:00 and peaking at an intense 11 at 13:00—a level where sun protection is crucial. From this pinnacle, the values start to decline, tapering off to 10 at 14:00 and then gradually decreasing through the afternoon and evening, with values of 6 at 16:00 and sliding down to 1 by 19:00. Plan your outdoor activities accordingly, and remember to protect your skin 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	2	low	45 min
09:00	3	moderate	30 min
10:00	6	high	25 min
11:00	8	very high	15 min
12:00	10	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	6	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 Princeton

Throughout the year, the UV Index exhibits notable seasonal changes, with high-risk months typically occurring from April to August. In these months, the UV Index reaches its peak at 11, indicating an extreme exposure category, particularly in June and July where burn time is reduced to just 10 minutes. Visitors and residents should take extra precautions during this period, including wearing protective clothing, applying broad-spectrum sunscreen, and seeking shade, especially from midday to early afternoon when UV radiation is strongest. As summer transitions into fall, the UV Index gradually decreases, with moderate levels seen from November to March, allowing for safer outdoor activities during these months. Being aware of these variations can help individuals enjoy the outdoors while minimizing the risk of UV-related health effects.

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	6	9	10	11	11	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