UV Index in Yonakuni, Japan

Last updated: May 3, 2025

In Yonakuni, Japan, understanding the UV Index is crucial for protecting your skin and overall health. With peak UV levels reaching as high as 13 during midday, it's essential to be aware of these fluctuations to prevent sunburn and reduce long-term skin damage. The subtropical climate characteristic of Yonakuni means that UV exposure can be intense, particularly during the summer months. By staying informed about the UV Index, you can enjoy your time outdoors while taking the necessary precautions to keep your skin safe and healthy.

Hourly UV Index in Yonakuni

The UV Index for today showcases a dramatic rise in intensity as the hours progress. Starting from a modest 1 at 07:00, it quickly escalates to 2 by 08:00, then surges to 4 by 09:00. The peak occurs at 12:00, where it reaches an impressive 12, making it crucial to take sun safety precautions. Continuing its ascent, the index hits a high of 13 at 13:00 before gradually declining, dropping back to 11 at 14:00. As the afternoon wanes, the values retract to 8 by 15:00, 5 by 16:00, and further down to 3 at 17:00. Finally, as twilight approaches, the index settles low at 1 by 18:00 and remains steady through 19:00. Ensuring protection during the peak hours is essential to safeguard against harmful UV exposure.

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	2	low	45 min
09:00	4	moderate	30 min
10:00	8	very high	15 min
11:00	11	extreme	10 min
12:00	12	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	3	moderate	30 min
18:00	1	low	45 min
19:00	1	low	45 min

Monthly UV Index Trends in Yonakuni

The UV Index exhibits significant seasonal variation, peaking in the summer months from March through August where it reaches an extreme level of 13, with a burn time of just 10 minutes. These months are the most critical for skin exposure, categorizing them as high-risk for sunburn. January and February begin with very high levels of 8 and 10, respectively, suggesting that even early in the year, precautions are necessary. As fall arrives, the UV Index decreases, dropping to 10 in October and 9 in November, before settling at a high level of 7 in December with a longer burn time of 25 minutes. Visitors and residents are advised to protect their skin by applying sunscreen, wearing protective clothing, and limiting sun exposure, especially during the high-risk months of March to September.

Monthly Maximum UV Index for Yonakuni, Japan

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

The table above highlights how UV exposure in Yonakuni 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.

Yonakuni'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
Yonakuni	8	10	12	13	13	13	13	13	12	10	9	7