Last updated: July 2, 2025
In Hachimantai, Japan, being aware of the UV Index is crucial for protecting your skin from harmful rays. Understanding UV levels helps prevent sunburns and maintain long-term skin health, especially during peak hours when the index reaches 10 between 11:00 AM and 12:00 PM. Hachimantai's Dfb climate brings diverse weather conditions, but with sunny days often leading to increased UV exposure, it's essential to stay informed. Embrace safety and enjoy the outdoors while keeping your skin's health a priority!
During the day, the UV Index experiences a dynamic shift, peaking in the late morning. Starting at 3 at 07:00, it escalates to reach a high of 10 by 11:00 and remains there until 12:00. As afternoon approaches, the index gradually declines, dropping back to 9 by 13:00, then to 7 at 14:00. By the mid to late afternoon, it continues its descent, falling to 5 at 15:00 and further down to 3 by 16:00. In the evening, the index diminishes significantly, plummeting to 1 at both 17:00 and 18:00, and finally reaching 0 by 19:00. This pattern highlights the importance of sun protection during the peak hours of 10:00 to 12:00 when the UV radiation is most intense.
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 3 | moderate | 30 min |
| 08:00 | 5 | moderate | 30 min |
| 09:00 | 7 | high | 25 min |
| 10:00 | 9 | very high | 15 min |
| 11:00 | 10 | very high | 15 min |
| 12:00 | 10 | very high | 15 min |
| 13:00 | 9 | very high | 15 min |
| 14:00 | 7 | high | 25 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 |
Throughout the year, UV exposure varies significantly, with distinct high-risk months typically occurring from April through September. In these months, the UV Index often reaches levels categorized as very high to extreme, with the most intense levels recorded in June and August (UV Index 11), where burn times drop to just 10 minutes. As we transition into spring, March marks a notable increase to a high risk with a UV Index of 6, and it escalates rapidly into the summer months. To safeguard your skin, it is advisable for visitors and residents alike to take precautions during these peak months by wearing broad-spectrum sunscreen, protective clothing, and seeking shade wherever possible. Conversely, during the winter months of January, February, and December, the UV levels are classified as moderate, allowing for safer outdoor activities with less risk of sunburn, although care is still recommended.
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 |
| Hachimantai | 3 | 4 | 6 | 8 | 9 | 11 | 10 | 11 | 9 | 6 | 4 | 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 |