UV Index in Koshima, Japan

Last updated: May 3, 2025

In Koshima, Japan, understanding the UV Index is crucial for safeguarding your skin against harmful sun exposure. With elevated UV levels peaking at 12 around midday, awareness of these values can significantly aid in sunburn prevention and long-term skin health. Koshima's Cfa climate brings a mix of sunny days and humidity, increasing UV exposure risks during the summer months. By staying informed about daily UV intensity, residents and visitors can take proactive measures to enjoy the outdoors while minimizing sun damage.

Hourly UV Index in Koshima

As the sun rises, the UV Index starts off low at 1 by 07:00. However, by 09:00, it climbs rapidly to 6, signaling a shift towards increasing intensity. The peak occurs at 12:00, where the UV Index reaches a significant 12, indicating a high risk of harm from unprotected sun exposure. As the afternoon progresses, values begin to decline, dropping to 9 by 14:00 and tapering off to 4 by 16:00. By the evening hours, the numbers dwindle back down to 1 by 18:00 and remain there until 19:00. Be mindful of the midday sun to protect your skin when the UV levels are at their highest!

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	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 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