UV Index in Isen, Japan

Last updated: July 2, 2025

In Isen, Japan, understanding the UV Index is crucial for protecting your skin and overall health. With peak UV levels soaring as high as 13 during midday, awareness of these numbers can help prevent painful sunburns and long-term skin damage. Given Isen's Cfa climate—characterized by hot summers and moderate sun exposure—residents and visitors alike should stay informed of daily UV risks to enjoy the outdoors safely. By recognizing when UV levels are elevated, you can take proactive measures to safeguard your skin while soaking in the beauty of this vibrant region.

Hourly UV Index in Isen

From 07:00 to 19:00, the UV Index exhibits a pronounced peak during midday hours, soaring to 13 between 12:00 and 13:00. The intensity rises steadily from a mild 1 at 07:00 to a substantial 12 at 11:00, indicating peak sun exposure just before noon. As the afternoon progresses, the index gradually declines, dropping to 5 by 16:00 and further to a safe 1 as the sun sets. With a dramatic increase during the late morning and early afternoon, it's crucial to stay protected against UV rays, especially when the index hits 9 and above between 10:00 and 14:00.

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	1	low	45 min
08:00	3	moderate	30 min
09:00	5	moderate	30 min
10:00	9	very high	15 min
11:00	12	extreme	10 min
12:00	13	extreme	10 min
13:00	13	extreme	10 min
14:00	11	extreme	10 min
15:00	8	very high	15 min
16:00	5	moderate	30 min
17:00	2	low	45 min
18:00	1	low	45 min
19:00	1	low	45 min

Monthly UV Index Trends in Isen

Throughout the year, UV levels exhibit significant seasonal variations, with March to September being particularly dangerous. The highest risk months—April through August—see UV Index values reaching extreme levels (12-13), where the recommended maximum exposure time is only 10 minutes. In contrast, January and December feature high UV Index values (6) with a burn time of 25 minutes, while February and October transition to very high levels (8-9) with shorter burn times. For both visitors and residents, it is crucial to take precautionary measures during high UV index months: use broad-spectrum sunscreen, wear protective clothing, and seek shade during peak sun hours. Always monitor the UV Index to ensure safe sun exposure.

Monthly Maximum UV Index for Isen, Japan

The monthly maximum UV Index (UVI) represents the highest UV radiation level recorded each month in Isen. 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 Isen, 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 Isen UV Index with Other Japan Cities

The table above highlights how UV exposure in Isen 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.

Isen'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
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
Isen	6	8	11	12	12	13	13	13	12	9	8	6