UV Index in Philadelphia, United States

Last updated: June 2, 2025

In Philadelphia, understanding the UV Index is crucial for protecting your skin from harmful ultraviolet rays. With late spring and summer months leading to notably high UV levels, particularly between midday to early afternoon, awareness of this index can significantly aid in sunburn prevention and promote long-term skin health. Philadelphia’s Cfa climate brings both sunny days and increased UV exposure, making it essential for residents and visitors alike to stay informed. By monitoring the UV Index, you can enjoy all that the City of Brotherly Love has to offer while keeping your skin safe and healthy!

Hourly UV Index in Philadelphia

At sunrise, the UV Index starts at a gentle 1 by 07:00, perfect for early risers enjoying the morning light. As the day progresses, it gradually climbs, reaching a moderate 3 by 09:00 and peaking at an intense 11 around 13:00 and 14:00. During these midday hours, the sun's rays are at their most powerful, making it crucial to seek shade or wear protective gear. Post-peak, the index begins to decline, descending to 5 by 17:00 and tapering off to 1 again by 19:00. This dynamic pattern highlights the importance of staying vigilant about sun protection, especially during 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	11	extreme	10 min
15:00	10	very high	15 min
16:00	7	high	25 min
17:00	5	moderate	30 min
18:00	3	moderate	30 min
19:00	1	low	45 min

Monthly UV Index Trends in Philadelphia

Throughout the year, UV exposure levels vary significantly, with high-risk months typically occurring from March to August when the UV Index reaches its peak at 11, categorized as extreme. March and April also feature very high levels, making these months crucial for sun safety awareness. Visitors and residents should be particularly cautious during this period, applying sunscreen regularly, wearing protective clothing, and seeking shade during peak hours. In contrast, the months of January, November, and December present a moderate UV Index of 3 to 5, allowing for more relaxed precautions, though it's still important to remain mindful of sun exposure. Always check local UV forecasts and adjust your sun safety practices accordingly to protect your skin year-round.

Monthly Maximum UV Index for Philadelphia, United States

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

The table above highlights how UV exposure in Philadelphia 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.

Philadelphia'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
Philadelphia	3	6	8	10	11	11	11	10	9	7	5	3
Houston UVI	5	8	9	11	11	12	12	11	10	9	7	5