UV Index in Greenwich, United States

Last updated: July 2, 2025

Understanding the UV Index is crucial for residents of Greenwich, United States, where the climate's warm temperatures can lead to heightened sun exposure. Being aware of UV levels helps in preventing sunburn and maintaining optimal skin health. With peak UV readings reaching as high as 9 between noon and 2 PM, the risk of skin damage increases significantly during these hours. As a member of the Cfa climate zone, Greenwich experiences its fair share of sunny days, making it essential to stay informed and protect yourself effectively—because prioritizing your skin's health is more than just shielding from the sun; it's a lifelong investment in wellness.

Hourly UV Index in Greenwich

The UV Index throughout the day presents a clear pattern of intensity, peaking at midday. Starting from a mild level of 1 at 07:00, the index rises steadily, reaching 2 by 08:00. The real surge occurs between 09:00 and 13:00, where it escalates from 4 to a striking 9—the highest point of the day. As the afternoon unfolds, the intensity slightly declines to 7 at 15:00, before tapering off to 5 at 16:00. The evening sees a further decrease, settling back to 2 by 18:00 and returning to 1 at 19:00. For those enjoying outdoor activities, it’s essential to take precautions, especially during the peak hours from 11:00 to 14:00 when the UV rays are most potent.

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
08:002low45 min
09:004moderate30 min
10:006high25 min
11:008very high15 min
12:009very high15 min
13:009very high15 min
14:009very high15 min
15:007high25 min
16:005moderate30 min
17:003moderate30 min
18:002low45 min
19:001low45 min

Monthly UV Index Trends in Greenwich

Throughout the year, the UV Index experiences notable fluctuations, with high-risk months typically spanning from March to September. In April and May, the Index peaks at 10, indicating a very high exposure category where the burn time is just 15 minutes. Consequently, during these months, it is crucial for both visitors and residents to take precautions such as wearing sunscreen, protective clothing, and sunglasses. The risk slightly diminishes in October with a UV Index of 6, shifting to lower levels by November and December, where the Index falls to 4 and 2, respectively. As the year progresses, individuals are encouraged to adjust their sun safety practices according to these seasonal changes to ensure their skin health remains a priority.

Monthly Maximum UV Index for Greenwich, United States

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in Greenwich. It measures the strength of ultraviolet radiation from the sun and helps assess the risk of sunburn and UV-related health issues.
JanFebMarAprMayJunJulAugSepOctNovDec35681010998642
Data source: Statistical UV Index data for Greenwich, 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 Greenwich UV Index with Other United States Cities

The table above highlights how UV exposure in Greenwich 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.
Greenwich's solar exposure compared to other cities in United States. Generated using Copernicus Atmosphere Monitoring Service information.
 JanFebMarAprMayJunJulAugSepOctNovDec
Greenwich35681010998642
Chicago UVI34689101098642
Brooklyn UVI35681010998642
New York City UVI35681010998642
Los Angeles UVI46891011111010754
Houston UVI589111112121110975