UV Index in Sanmu, Japan

Last updated: May 3, 2025

Understanding the UV Index in Sanmu, Japan, is crucial for protecting your skin and overall health. With peak UV levels often reaching as high as 11, even a brief exposure during midday can lead to sunburn and long-term skin damage. In this Cfa climate zone, sunny days can result in significant UV radiation, making it vital for residents and visitors to stay informed about daily UV levels. By keeping an eye on the UV Index, you can take proactive measures to safeguard yourself against harmful sun exposure, ensuring that your outdoor activities remain enjoyable and safe.

Hourly UV Index in Sanmu

As the sun rises, the UV Index begins its ascent, starting at a modest 2 at 07:00. The real intensity kicks in by 10:00, peaking at an impressive 11 from 11:00 to 12:00, signaling the need for sun protection. After the midday sun, the index gradually declines, dipping to 4 by 15:00 before sliding down to 1 by 17:00. As the evening approaches, the UV rays fade to 0 by 19:00, marking a safe end to outdoor activities. This data underscores the importance of staying sun-safe during the peak hours!

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.
Time	UVI	Category	Time to Burn
07:00	2	low	45 min
08:00	5	moderate	30 min
09:00	7	high	25 min
10:00	10	very high	15 min
11:00	11	extreme	10 min
12:00	11	extreme	10 min
13:00	9	very high	15 min
14:00	7	high	25 min
15:00	4	moderate	30 min
16:00	2	low	45 min
17:00	1	low	45 min
18:00	1	low	45 min
19:00	0	low	45 min

Monthly UV Index Trends in Sanmu

Throughout the year, UV Index levels display significant seasonal changes, with the highest readings occurring from May to August, where the index reaches an extreme level of 11. This period signifies a high-risk for UV exposure, with a dangerously quick burn time of only 10 minutes. In contrast, the winter months of January, February, November, and December feature moderate UV levels, with indices ranging from 3 to 5 and a burn time of 30 minutes or more. Visitors and residents should take precautions during the peak months, particularly by seeking shade, wearing protective clothing, and applying sunscreen, as skin damage can occur rapidly during this time. It's crucial to remain vigilant during the spring and early fall as well, when UV levels are still notably high, especially in March and September.

Monthly Maximum UV Index for Sanmu, Japan

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in Sanmu. It measures the strength of ultraviolet radiation from the sun and helps assess the risk of sunburn and UV-related health issues.

Data source: Statistical UV Index data for Sanmu, 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 Sanmu UV Index with Other Japan Cities

The table above highlights how UV exposure in Sanmu 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.

Sanmu's solar exposure compared to other cities in Japan. Generated using Copernicus Atmosphere Monitoring Service information.
	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Sapporo UVI	2	3	6	7	9	9	9	10	8	5	3	2
Sanmu	3	5	8	9	11	11	11	11	9	7	5	4
Yokohama UVI	3	5	8	9	11	11	11	11	10	7	5	4
Tokyo UVI	3	5	8	9	11	11	11	11	10	7	5	4
Nagoya UVI	4	6	8	10	11	11	11	11	10	7	5	3
Osaka UVI	4	6	8	11	11	11	12	11	10	7	5	3