UV Index in Suwa, Japan

Last updated: July 2, 2025

Understanding the UV Index is crucial for residents of Suwa, Japan, where the interplay of weather and altitude can lead to higher UV exposure. With the city’s Dfb climate characterized by distinct seasons, awareness of UV levels is essential for preventing sunburn and maintaining skin health, especially during the midday hours when the index peaks at 12. As the sun rises in Suwa, UV levels can escalate quickly, hitting a maximum of 10 by late morning and staying elevated throughout the afternoon. By staying informed about the UV Index, you can effectively protect yourself and enjoy the outdoors safely!

Hourly UV Index in Suwa

As the sun rises, the UV Index begins its ascent, reaching maximum levels early in the day. At 07:00, it starts at a mild 2, but by 08:00, it spikes to 5. The peak occurs between 11:00 and 12:00, when the index hits its highest at 12, indicating a significant potential for skin damage without protection. The afternoon sees a gradual decline; it drops to 8 by 14:00 and continues to lessen, settling at 6 by 15:00, before tapering off to 3 at 16:00, and then further to 1 by 18:00. As the day winds down, the UV Index finally drops to a safe 0 by 19:00, reminding us of the importance of sun protection during those peak hours!

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	5	moderate	30 min
09:00	7	high	25 min
10:00	10	very high	15 min
11:00	12	extreme	10 min
12:00	12	extreme	10 min
13:00	11	extreme	10 min
14:00	8	very high	15 min
15:00	6	high	25 min
16:00	3	moderate	30 min
17:00	2	low	45 min
18:00	1	low	45 min
19:00	0	low	45 min

Monthly UV Index Trends in Suwa

Throughout the year, UV index levels fluctuate, with the most significant increases occurring from March to September. During these months, particularly in May, June, July, and August, the UV index reaches its peak at 12, categorized as extreme, with a burn time of just 10 minutes. March and April also present high risks, featuring very high UV levels of 9 and 10 respectively. Visitors and residents should be particularly vigilant in these high-risk months, applying sunscreen, wearing protective clothing, and seeking shade whenever possible. As UV levels decrease from late summer into fall and winter, with January and December categorized as having moderate exposure (UV index 4), precautions remain advisable to ensure skin protection year-round.

Monthly Maximum UV Index for Suwa, Japan

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

The table above highlights how UV exposure in Suwa 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.

Suwa'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
Suwa	4	6	9	10	11	11	12	12	10	7	5	4