UV Index in Yachiyo, Japan

Last updated: July 2, 2025

Understanding the UV Index is essential for residents of Yachiyo, Japan, where sunny days and a Cfa climate create perfect conditions for outdoor activities. Awareness of UV levels can significantly contribute to sunburn prevention and long-term skin health, protecting you from harmful ultraviolet radiation. In Yachiyo, the UV Index peaks at midday, reaching levels as high as 11, signaling a need for vigilance. By staying informed of the daily UV forecast, you can enjoy the beautiful outdoors safely while minimizing the risks associated with high UV exposure.

Hourly UV Index in Yachiyo

The UV Index throughout the day presents a dynamic picture of sun exposure. As early as 7:00 AM, the index starts at a mild 2, ramping up to a moderate 4 by 8:00 AM. The sun's intensity peaks around 11:00 AM and 12:00 PM with a striking 11, marking the height of caution for outdoor activities. As we move into the afternoon, the index gradually declines, dropping to 8 by 2:00 PM and further to 5 by 3:00 PM. The evening brings relief, with the UV Index decreasing to a 1 by 5:00 PM and finally hitting 0 by 7:00 PM. It’s clear that the midday hours pose the greatest risk, so sun safety measures are essential during those peak times.

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
10:009very 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 Yachiyo

The seasonal UV variations indicate a significant increase in UV exposure from winter to summer, with high-risk months emerging from April through August. During this period, the UV Index peaks at 11 (extreme), particularly in June, July, and August, where the burn time drops to just 10 minutes. Visitors and residents are advised to take precautionary measures during these months, such as seeking shade, wearing protective clothing, and applying sunscreen frequently. As the UV levels decrease in the fall and winter months, with indices dropping to 3 in January and December, the risk of sunburn diminishes. However, maintaining sun safety practices year-round remains essential for health and well-being.

Monthly Maximum UV Index for Yachiyo, Japan

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in Yachiyo. It measures the strength of ultraviolet radiation from the sun and helps assess the risk of sunburn and UV-related health issues.
JanFebMarAprMayJunJulAugSepOctNovDec4579101111119753
Data source: Statistical UV Index data for Yachiyo, 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 Yachiyo UV Index with Other Japan Cities

The table above highlights how UV exposure in Yachiyo 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.
Yachiyo's solar exposure compared to other cities in Japan. Generated using Copernicus Atmosphere Monitoring Service information.
 JanFebMarAprMayJunJulAugSepOctNovDec
Sapporo UVI2367999108532
Yachiyo3579101111119753
Yokohama UVI35891111111110754
Tokyo UVI35891111111110754
Nagoya UVI468101111111110753
Osaka UVI468111111121110753