UV Index in Princeton, United States

Last updated: May 3, 2025

Understanding the UV Index is crucial for residents of Princeton, United States, as it plays a vital role in safeguarding your skin health from harmful ultraviolet radiation. With the area's Dfa climate, Princeton experiences varying UV levels throughout the day, peaking at a high of 9 between noon and 1 PM. Recognizing the UV Index not only helps in preventing painful sunburns but also reduces the long-term risks associated with skin damage. Being aware of these levels allows you to take necessary precautions, ensuring that your outdoor activities remain enjoyable while protecting your skin from sun exposure risks.

Hourly UV Index in Princeton

The UV Index reveals a dynamic day of sun exposure, starting with a gentle 1 at 07:00 and gradually ramping up as the morning unfolds. By 09:00, it climbs to 4, reaching a more noteworthy 6 at 10:00. As the sun reaches its zenith, the UV Index peaks at 9 during the crucial hours of 12:00 and 13:00, indicating a high risk of harm from unprotected sun exposure. The intensity begins to wane after 14:00, settling to 7 at 15:00 before gradually decreasing to 1 by 19:00. Remember to protect your skin between 11:00 and 14:00 when the sun’s rays are at their most dangerous!

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	6	high	25 min
11:00	7	high	25 min
12:00	9	very high	15 min
13:00	9	very high	15 min
14:00	8	very high	15 min
15:00	7	high	25 min
16:00	5	moderate	30 min
17:00	3	moderate	30 min
18:00	2	low	45 min
19:00	1	low	45 min

Monthly UV Index Trends in Princeton

Throughout the year, UV exposure varies significantly, with the highest risk months occurring from April to September when the index reaches very high to extreme levels. Specifically, June stands out with a UV Index of 11, where a mere 10 minutes of unprotected sun exposure can lead to skin damage. In contrast, during the winter months of January and February, the UV Index remains lower, categorized as moderate, allowing for a safer 30-minute burn time. Visitors and residents are advised to take necessary precautions during high-risk months, such as applying broad-spectrum sunscreen, wearing protective clothing, and seeking shade during peak sunlight hours, to minimize their risk of UV-related skin damage.

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	8	9	11	10	9	8	6	4	2
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