UV Index in Koshima, Japan

Last updated: July 2, 2025

Understanding the UV Index in Koshima, Japan, is crucial for protecting your skin and maintaining overall health. With the region’s climate classified as Cfa, residents and visitors alike should be aware of the heightened UV exposure, especially during the peak hours around noon when the index can soar to 13—an indication of extreme risk for sunburn. By grasping the importance of UV levels, you can take proactive measures to prevent skin damage and enjoy the vibrant outdoors safely. As Koshima often experiences intense sunlight, staying informed about UV Index ratings is key to safeguarding your skin and enjoying a healthy lifestyle.

Hourly UV Index in Koshima

The UV Index shows a dramatic rise throughout the morning, starting at a mild 1 at 07:00 and escalating to 3 by 08:00. As the sun climbs higher, the index reaches a peak of 13 at 12:00, signaling a level of exposure that calls for protective measures. Intensity slightly decreases in the afternoon, dropping to 10 at 14:00 and 8 at 15:00, before gradually declining to a safe 1 by 19:00. Overall, the day presents a clear warning for outdoor activities, emphasizing the need for sunscreen and shade during the midday hours when UV radiation is at its strongest. Stay protected!

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	6	high	25 min
10:00	9	very high	15 min
11:00	11	extreme	10 min
12:00	13	extreme	10 min
13:00	12	extreme	10 min
14:00	10	very high	15 min
15:00	8	very high	15 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 Koshima

Throughout the year, the UV Index exhibits significant seasonal variations, with the highest risks occurring between March and September. During this period, particularly in June, July, and August, the UV Index reaches its peak at 13, indicating extreme exposure levels with a burn time of just 10 minutes. Conversely, the UV levels are generally moderate in January and December (UV Index 5) and high in February and November (UV Index 7), where burn times extend to 25-30 minutes. Residents and visitors are strongly advised to take precautionary measures, especially from March to September, by seeking shade, wearing protective clothing, and applying sunscreen, to reduce the risk of skin damage from UV radiation.

Monthly Maximum UV Index for Koshima, Japan

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

The table above highlights how UV exposure in Koshima 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.

Koshima'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
Koshima	5	7	10	11	12	12	13	13	11	8	7	5