Last updated: June 2, 2025
In Omachi, Japan, understanding the UV Index is crucial for safeguarding your skin and overall health. With UV levels peaking at 12 during midday, awareness of these fluctuations can help prevent sunburn and long-term skin damage. Given Omachi's Dfb climate, known for its distinct seasons and varied weather, residents and visitors alike must be vigilant about UV exposure, especially during the summer months. By staying informed about the UV Index, you can enjoy the beautiful outdoor scenery while keeping your skin safe.
The UV Index throughout the day presents an intriguing ebb and flow. Starting off at a gentle 2 at 07:00, it quickly climbs to 5 by 08:00 as the sun rises higher. The peak radiance hits at 12:00, reaching an intense 12, signaling a time when protection from the sun is crucial. From 11:00 to 13:00, the index remains high, hovering around 11 and 12, before beginning a noticeable decline. By 14:00, it drops to 8 and continues to fall, dropping to a mere 1 by 18:00 and finally resting at 0 after sunset. This data highlights the importance of staying sun-safe during the mid-day hours when UV exposure is at its 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 | 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 |
Throughout the year, UV exposure levels exhibit significant seasonal changes, with peak risks occurring during the summer months. January and December have a moderate UV Index of 4, where a burn can occur in 30 minutes. As winter transitions to spring, February sees a rise to a high UV Index of 6, with a shorter burn time of 25 minutes. The spring and summer months are marked by very high to extreme UV levels, peaking in July and August at a 12, meaning skin can burn in as little as 10 minutes. Notably, March and April also maintain a high level of risk with a UV Index of 10. As fall approaches, the UV Index begins to decline, dropping to 10 in September and 7 in October, before reducing further to moderate levels in November. Visitors and residents should be particularly cautious from March through August, practicing sun safety by seeking shade, using sunscreen, and wearing protective clothing during these high-risk months.
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 |
| Omachi | 4 | 6 | 10 | 10 | 11 | 11 | 12 | 12 | 10 | 7 | 5 | 4 |