UV Index in Nagasaki, Japan

Last updated: July 2, 2025

In the beautiful city of Nagasaki, Japan, being aware of the UV Index is crucial for protecting your skin and maintaining overall health. With UV radiation levels peaking in the mid-afternoon, understanding the risks can help you prevent sunburn and long-term skin damage. Nagasaki's Cfa climate brings warm summers and mild winters, resulting in significant UV exposure throughout the year. On a typical day, UV levels can soar to 12 between noon and early afternoon, making it essential to plan your outdoor activities accordingly and take precautions to safeguard your skin. Stay informed to enjoy the sun safely!

Hourly UV Index in Nagasaki

The UV Index provides a clear snapshot of sun exposure throughout the day, peaking at 12 around noon. Starting the morning at a mild level of 1 at 07:00, the index swiftly climbs, reaching 11 by 11:00. The intensity plateaus at its highest point of 12 between 12:00 and 13:00, indicating a critical time for sun safety. As the afternoon progresses, the UVI declines, dropping to 10 at 14:00, and gradually softening to 4 by 16:00. By the evening hours, the index falls back to a comfortable 1 by 18:00, making later hours more forgiving for outdoor activities. Stay protected and plan your sun exposure wisely!

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	8	very high	15 min
11:00	11	extreme	10 min
12:00	12	extreme	10 min
13:00	12	extreme	10 min
14:00	10	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 Nagasaki

Throughout the year, the UV Index exhibits significant seasonal variations, with spring and summer months posing the highest risk of UV exposure. From March to September, the index reaches very high to extreme levels—particularly during April to August, where it peaks at 12 in July and August. During these months, the burn time shortens dramatically to just 10 minutes, indicating a critical need for sun protection. Conversely, January and December record the lowest UV levels with a moderate exposure category, allowing for more extended exposure times of 30 minutes. Visitors and residents are advised to take precautions, especially from March to September, by wearing protective clothing, applying sunscreen, and seeking shade during peak hours to minimize the risks associated with high UV exposure.

Monthly Maximum UV Index for Nagasaki, Japan

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

The table above highlights how UV exposure in Nagasaki 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.

Nagasaki'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
Nagasaki	4	6	8	11	11	11	12	12	11	8	6	4