UV Index in Flagstaff, United States

Last updated: June 2, 2025

Understanding the UV Index is crucial for residents and visitors in Flagstaff, Arizona, where the sun’s rays can be deceptively strong, especially during peak hours. Awareness of UV levels is vital for preventing sunburn and maintaining skin health, allowing you to enjoy the outdoors safely. Flagstaff, with its Csb climate, experiences significant UV exposure, illustrating the importance of protecting your skin from harm. With peak UV Index values soaring as high as 13 during midday, it’s essential to check the UV Index regularly and take appropriate precautions to ensure a healthy, sun-conscious lifestyle in this beautiful mountain town.

Hourly UV Index in Flagstaff

The UV Index for today reveals a dramatic rise in sunlight intensity as the day progresses. From a gentle start at 07:00 with a value of 2, the index climbs steadily to reach a peak of 13 by 12:00. 11:00 marks the onset of extreme caution, hitting 11, and swiftly moves to its highest point at 12:00. As the afternoon unfolds, the sun’s intensity begins to wane, dropping to 11 at 14:00, then gradually decreasing to 5 by 16:00. By the evening, the index returns to a low of 1 at both 18:00 and 19:00. Remember, during those peak hours, it's essential to protect your skin and stay hydrated!

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
07:002low45 min
08:003moderate30 min
09:006high25 min
10:009very high15 min
11:0011extreme10 min
12:0013extreme10 min
13:0012extreme10 min
14:0011extreme10 min
15:008very high15 min
16:005moderate30 min
17:003moderate30 min
18:001low45 min
19:001low45 min

Monthly UV Index Trends in Flagstaff

Throughout the year, UV Index levels fluctuate, indicating varying risks for skin exposure. The high-risk months are primarily from March to September, where the UV Index peaks at 13 in both June and July, classified as extreme, resulting in a burn time of only 10 minutes. Visitors and residents should prioritize skin protection during these months with appropriate sunscreen, protective clothing, and seeking shade during peak hours. The months of February and October also present very high UV levels of 8, with shorter burn times of 15 minutes, necessitating caution. Conversely, January, November, and December feature moderate to high UV levels, with more forgiving burn times, though protective measures should still be considered. Emphasizing sun safety year-round is essential for both health and well-being.

Monthly Maximum UV Index for Flagstaff, United States

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in Flagstaff. It measures the strength of ultraviolet radiation from the sun and helps assess the risk of sunburn and UV-related health issues.
JanFebMarAprMayJunJulAugSepOctNovDec589111213131211864
Data source: Statistical UV Index data for Flagstaff, 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 Flagstaff UV Index with Other United States Cities

The table above highlights how UV exposure in Flagstaff 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.
Flagstaff'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
Flagstaff589111213131211864