UV Index in Yokohama, Japan

Last updated: July 2, 2025

Understanding the UV Index is crucial for residents and visitors in Yokohama, Japan, as it provides essential information about sun exposure risks throughout the day. With a climate characterized by humid subtropical conditions (Cfa), the city often experiences elevated UV levels, especially during peak hours. By being aware of UV levels, individuals can take proactive measures to protect their skin from harmful effects such as sunburn and long-term damage. Notably, the UV Index in Yokohama can reach a maximum of 11 between noon and 1 PM, indicating a high potential for UV radiation that warrants careful consideration and sun safety practices. Stay informed and safeguard your skin while enjoying Yokohama's beautiful outdoors!

Hourly UV Index in Yokohama

As the sun rises, the UV Index begins its climb, starting at a modest 2 at 7:00 AM. By 8:00 AM, it gains momentum, reaching 4, but the real peak arrives between 10:00 AM and 12:00 PM, where it soars to a striking 11. This is the time to seek shade or wear protective gear, as the sun's rays are at their harshest. After noon, the intensity wanes slightly with readings of 10 at 1:00 PM and gently dropping to 8 by 2:00 PM. As the afternoon turns to evening, the index cools down to 5 at 3:00 PM, before dipping to 3 by 4:00 PM, and ultimately settling at 1 by 6:00 PM. By sunset, the danger fades, leaving a 0 UV reading at 7:00 PM. Keep an eye on the UV Index to enjoy the sun 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.
TimeUVICategoryTime to Burn
07:002low45 min
08:004moderate30 min
09:007high25 min
10:0010very high15 min
11:0011extreme10 min
12:0011extreme10 min
13:0010very high15 min
14:008very high15 min
15:005moderate30 min
16:003moderate30 min
17:001low45 min
18:001low45 min
19:000low45 min

Monthly UV Index Trends in Yokohama

As the seasons change, the UV Index fluctuates significantly, influencing the risk of sun exposure throughout the year. January and February start with a moderate UV Index of 3 and 5, allowing for a burn time of 30 minutes. However, by March, the UV Index jumps to 8, which is categorized as very high, reducing safe exposure to just 15 minutes. The peak months for UV radiation are May through August, where the Index reaches an extreme level of 11, necessitating a mere 10 minutes of exposure before risking sunburn. September begins a gradual decline to a very high index of 10, while October and onward return to moderate levels. Visitors and residents should be particularly cautious from March to August—wearing protective clothing, applying sunscreen, and seeking shade to minimize UV damage during these high-risk months.

Monthly Maximum UV Index for Yokohama, Japan

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in Yokohama. It measures the strength of ultraviolet radiation from the sun and helps assess the risk of sunburn and UV-related health issues.
JanFebMarAprMayJunJulAugSepOctNovDec45891111111110753
Data source: Statistical UV Index data for Yokohama, 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 Yokohama UV Index with Other Japan Cities

The table above highlights how UV exposure in Yokohama compares to other major locations across Japan. This comparison helps travelers and residents better understand regional sun intensity and plan outdoor activities with sun safety in mind.
Yokohama's solar exposure compared to other cities in Japan. Generated using Copernicus Atmosphere Monitoring Service information.
 JanFebMarAprMayJunJulAugSepOctNovDec
Sapporo UVI2367999108532
Yokohama35891111111110754
Tokyo UVI35891111111110754
Nagoya UVI468101111111110753
Osaka UVI468111111121110753