Last updated: June 2, 2025
Understanding the UV Index in Suwa, Japan is crucial for safeguarding your skin and overall health. The UV Index provides essential information about the strength of ultraviolet radiation from the sun, helping residents and visitors alike to take necessary precautions against sunburn and long-term skin damage. In Suwa, where the Dfb climate brings a mix of seasonal sun exposure, peak UV levels can soar to 11 between 11:00 AM and 12:00 PM, highlighting the need for vigilance during those hours. By staying informed about UV levels, you can enjoy the beautiful outdoors while protecting your skin from harmful effects.
The UV Index throughout the day exhibits a clear peak around midday, reflecting the sun's intensity. Starting from a mild 2 at 07:00, it swiftly rises to a moderate 5 by 08:00. By 09:00, the index escalates to a more intense 7, reaching a notable 10 at 10:00, and hitting its maximum of 11 at both 11:00 and 12:00. As the afternoon progresses, the index begins to decline, dropping to 10 at 13:00, then gradually lowering to 8 at 14:00 and 6 by 15:00. The evening sees a rapid decrease, with values falling to 3 at 16:00, then to 2 at 17:00, and finally tapering off to 1 at 18:00 and 0 by 19:00. This pattern emphasizes the importance of sun protection during the peak hours of 11:00 to 14:00 when UV exposure is highest.
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 | 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 | 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 |
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.
UV Risk Categories
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 |