UV Index in Isa, Japan

Last updated: June 2, 2025

In Isa, Japan, being aware of the UV Index is crucial for protecting your skin and overall health. Understanding UV levels helps you prevent sunburn and long-term skin damage, especially during peak exposure times. Isa’s humid subtropical climate (Cfa) brings high UV levels, with the index soaring to a maximum of 12 around noon. By staying informed about UV radiation, you can enjoy the sunny days of Isa while minimizing risks to your skin.

Hourly UV Index in Isa

As the sun rises, the UV Index begins its ascent, starting at a modest 2 at 07:00. By 08:00, it reaches 3, signaling the start of a day filled with increasing sun intensity. The index climbs to 6 by 09:00, peaking dramatically at 12 during noon. Between 11:00 and 13:00, the UV Index hovers around a remarkable 11, emphasizing the need for protection against the sun’s rays. As the afternoon rolls on, values gradually decline, settling at 9 by 14:00 and then tapering off to 7 at 15:00. By late afternoon, the index drops to 4 at 16:00 and continues its descent to 1 by the evening, reminding us of the dynamic nature of sunlight throughout the day. Stay informed and protected 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	3	moderate	30 min
09:00	6	high	25 min
10:00	8	very high	15 min
11:00	11	extreme	10 min
12:00	12	extreme	10 min
13:00	11	extreme	10 min
14:00	9	very high	15 min
15:00	7	high	25 min
16:00	4	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 Isa

Throughout the year, the UV Index shows notable seasonal changes, with the highest risk occurring from March to September. During these months, the index reaches extreme levels, particularly peaking in August with a UV Index of 13. Visitors and residents should exercise caution during high-risk months and, ideally, limit direct sun exposure to less than 10 minutes daily between April and September. In contrast, the UV Index is relatively moderate in January and December, with burn times of 30 minutes. To minimize the risk of skin damage, it is essential to apply sunscreen, wear protective clothing, and seek shade, especially during peak hours from late morning to early afternoon.

Monthly Maximum UV Index for Isa, Japan

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

The table above highlights how UV exposure in Isa 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.

Isa'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
Isa	5	6	9	11	12	12	12	13	11	8	6	4