UV Index in Key West, United States

Last updated: June 2, 2025

Understanding the UV Index in Key West, United States, is crucial for anyone looking to enjoy the sun safely in this tropical paradise. With soaring UV levels peaking around midday, knowing the intensity of ultraviolet radiation is vital for effective sunburn prevention and maintaining skin health. Key West’s sunny and humid climate can expose residents and visitors to significant UV risks, especially during the summer months. Staying informed about the UV Index helps you protect your skin and enjoy the beautiful outdoor lifestyle this vibrant location has to offer.

Hourly UV Index in Key West

As the sun rises on this bright day, the UV Index starts off relatively low, peaking at just 1 at both 7:00 AM and 8:00 AM. However, by 9:00 AM, it jumps to 3, signaling an increase in UV exposure. The intensity escalates quickly, reaching a notable 6 by 10:00 AM. The real intensity hits its peak at 12:00 PM, when the UV Index soars to a striking 12, followed closely by a high of 13 at 1:00 PM. Over the next few hours, the index gradually diminishes, but still remains significant with 10 at 3:00 PM and 7 by 4:00 PM. As evening approaches, the levels continue to decline, returning to 1 once dusk settles in at 7:00 PM. Be sure to protect your skin!

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.
TimeUVICategoryTime to Burn
07:001low45 min
08:001low45 min
09:003moderate30 min
10:006high25 min
11:009very high15 min
12:0012extreme10 min
13:0013extreme10 min
14:0012extreme10 min
15:0010very high15 min
16:007high25 min
17:004moderate30 min
18:002low45 min
19:001low45 min

Monthly UV Index Trends in Key West

Throughout the year, UV index levels vary significantly, with the highest risk months occurring from March to September, peaking at UV Index 13 in June. The extreme exposure category (UV Index 11-13) highlights the urgent need for protective measures, as the burn time during these months drops to just 10 minutes. February also poses a threat with a very high index of 9 and a burn time of only 15 minutes. Visitors and residents are strongly advised to take precautions, such as wearing sunscreen, protective clothing, and seeking shade during peak sunlight hours, especially during the high UV months of March through September. As the year progresses, the index generally decreases, with January and December being relatively safer months, registering high levels but allowing for longer exposure times of 25 minutes. Remaining vigilant about UV exposure year-round is essential for skin protection and overall health.

Monthly Maximum UV Index for Key West, United States

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in Key West. It measures the strength of ultraviolet radiation from the sun and helps assess the risk of sunburn and UV-related health issues.
JanFebMarAprMayJunJulAugSepOctNovDec79111212131212111086
Data source: Statistical UV Index data for Key West, 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 Key West UV Index with Other United States Cities

The table above highlights how UV exposure in Key West 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.
Key West's solar exposure compared to other cities in United States. Generated using Copernicus Atmosphere Monitoring Service information.
 JanFebMarAprMayJunJulAugSepOctNovDec
Chicago UVI34689101098642
Brooklyn UVI35681010998642
New York City UVI35681010998642
Los Angeles UVI46891011111010754
Houston UVI589111112121110975
Key West79111212131212111086