UV Index in Philadelphia, United States

Last updated: July 2, 2025

In Philadelphia, understanding the UV Index is crucial for safeguarding your skin and overall health. With summer temperatures often reaching high levels, being aware of UV exposure can help you prevent sunburn and long-term skin damage. The city's humid subtropical climate presents unique challenges, as UV levels peak dramatically throughout the day—reaching a maximum of 11 around midday. Whether you're enjoying a sunny day outdoors or just heading out for lunch, keeping an eye on the UV Index can help you take the necessary precautions to enjoy Philadelphia’s vibrant outdoor life, while protecting your skin.

Hourly UV Index in Philadelphia

As the sun rises, the UV Index gradually increases from a low of 1 at 07:00, signaling a relatively mild start to the day. By 10:00, it reaches a moderate 4, but the real intensity kicks in around 11:00, peaking at a staggering 11 by 13:00. This two-hour stretch showcases the sun's strength, making it crucial for sun safety awareness. As the afternoon wanes, the UV Index starts to decline, falling back to 7 by 16:00 and settling at a gentle 3 by 18:00. With this data, remember to protect your skin during those peak hours to enjoy the sunny day safely!

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	2	low	45 min
10:00	4	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