UV Index in Nagai, Japan

Last updated: August 1, 2025

Awareness of the UV Index is crucial in Nagai, Japan, where the climate fosters plenty of sunshine, especially during the summer months. Understanding UV levels is key to protecting your skin and preventing sunburn, as excessive exposure can have long-term health effects. In Nagai, the UV Index can reach a high of 11 during peak hours, indicating a very high risk of harm from unprotected sun exposure. With typical ecological conditions in the Dfb climate zone, residents and visitors alike should be vigilant about sun protection, particularly between 10 AM and 2 PM, when UV levels are at their peak. Stay informed and protect your skin to enjoy the beautiful days ahead!

Hourly UV Index in Nagai

The UV Index (UVI) exhibits a notable pattern throughout the day. Starting at 2 at 7:00 AM, it gradually rises, peaking at 11 by noon and 1:00 PM. This high level of UV exposure indicates that sun protection is essential during these hours. As the afternoon progresses, the UVI begins to dip, dropping to 7 by 2:00 PM and then declining further to 5 by 3:00 PM. By late afternoon, the sunlight's intensity reduces significantly, with the UVI falling to 1 by 5:00 PM and remaining minimal through 6:00 PM and 7:00 PM. This data underscores the importance of taking precautions during peak hours while enjoying the outdoors.

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	4	moderate	30 min
09:00	7	high	25 min
10:00	10	very high	15 min
11:00	11	extreme	10 min
12:00	11	extreme	10 min
13:00	10	very high	15 min
14:00	8	very high	15 min
15:00	5	moderate	30 min
16:00	3	moderate	30 min
17:00	1	low	45 min
18:00	1	low	45 min
19:00	0	low	45 min

Monthly UV Index Trends in Nagai

Throughout the year, UV levels demonstrate significant seasonal variations, with high-risk months typically occurring from March through August. During this period, the UV Index peaks at 11 in June, July, and August, marking it as an extreme risk category with a burn time of just 10 minutes. In contrast, the lowest UV Index readings, categorized as moderate, occur in January, February, November, and December, allowing for 30-minute exposure without immediate risk of skin damage. Visitors and residents should prioritize sun safety measures, particularly in the high-risk months—using sunscreen, wearing protective clothing, and seeking shade during peak hours to minimize potential harm from intense UV radiation.

Monthly Maximum UV Index for Nagai, Japan

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

The table above highlights how UV exposure in Nagai 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.

Nagai'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
Nagai	3	5	8	9	10	11	11	11	9	7	5	3
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