Last updated: June 2, 2025
Understanding the UV Index is crucial for residents and visitors of Tosashimizu, Japan, where the subtropical climate exposes us to varying levels of ultraviolet radiation throughout the year. As the UV levels peak, particularly around midday with values soaring to 12, staying informed helps prevent sunburn and protects long-term skin health. Being aware of these levels allows you to take proactive measures, such as seeking shade or applying sunscreen, to mitigate risk. With Tosashimizu's warm climate and significant UV exposure, understanding the daily UV index is key to enjoying the sun safely while keeping your skin in top condition.
As the day unfolds, the UV Index climbs steadily, peaking at a striking 12 around noon, signaling a high risk for skin damage without protection. Early risers at 07:00 encounter a mild 2, but the intensity increases quickly, reaching 9 by 10:00 and a critical 11 by 11:00. From 12:00 to 13:00, the index holds its highest point at 12, making it essential to seek shade or apply sunscreen. After 13:00, the UV levels gradually decrease, dropping back to a manageable 4 by 16:00 and winding down to a safe 1 by 18:00. This hourly data serves as a reminder to take sun safety precautions, especially during peak hours.
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 2 | low | 45 min |
| 08:00 | 4 | moderate | 30 min |
| 09:00 | 6 | high | 25 min |
| 10:00 | 9 | very high | 15 min |
| 11:00 | 11 | extreme | 10 min |
| 12:00 | 12 | extreme | 10 min |
| 13:00 | 11 | extreme | 10 min |
| 14:00 | 9 | very high | 15 min |
| 15:00 | 6 | 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 |
Throughout the year, the UV Index experiences significant variations, peaking in the summer months. From May to August, the index reaches an extreme level of 12, indicating a burn time of only 10 minutes; therefore, it is crucial for visitors and residents to take extra precautions during this period, such as wearing sunscreen, sunglasses, and protective clothing. March and April also present high levels, with indexes of 9 and 10, respectively, making these months a time to be vigilant as well. Conversely, during the winter months of January and December, the index drops to levels categorized as moderate (UV Index 4), allowing for longer burn times of 30 minutes. Overall, the high-risk months to be particularly cautious are May through August, and to ensure safety, it’s advisable to seek shade and limit sun exposure during peak hours.
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 |
| Tosashimizu | 4 | 6 | 9 | 10 | 12 | 12 | 12 | 12 | 10 | 7 | 6 | 4 |