Last updated: July 2, 2025
In Sendai, Japan, staying informed about the UV Index is crucial for safeguarding your skin and overall health. Understanding UV levels helps prevent sunburns and long-term skin damage, enabling you to enjoy the outdoors safely. With Sendai's Cfa climate, characterized by warm summers and considerable sun exposure, the UV index can peak at 10 during midday, signaling a high risk for harmful effects. Familiarizing yourself with these levels empowers you to take necessary precautions, ensuring fun in the sun without compromising your skin's health.
The UV Index for the day starts off gently at 3 by 7:00 AM, gradually elevating as the sun climbs higher in the sky. By 9:00 AM, it reaches 7, signaling the onset of stronger rays. The peak occurs between 11:00 AM and 12:00 PM, where it hits a maximum of 10, indicating a high risk of harm from unprotected sun exposure. As the afternoon progresses, the index starts to decline, dipping to 5 by 3:00 PM and further to 1 by 5:00 PM, leading to a comfortable evening. As night falls at 7:00 PM, the UV index drops to 0, marking the end of sun-related concerns for the day. Remember to take precautions during peak hours to protect your skin!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 3 | moderate | 30 min |
| 08:00 | 4 | 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 |
As the seasons change, so does the UV Index, impacting both visitors and residents. From January to February, the UV Index remains at a moderate level (3-4), allowing for 30 minutes of sun exposure without significant risk. However, as spring approaches in March, the index climbs to high (7), reducing safe exposure to 25 minutes. The peak UV Index occurs during summer months, notably in July and August, where it reaches an extreme level (11) with a mere 10 minutes of safe exposure. September sees a decline to very high (9), while October returns to high (6) conditions, each allowing for a bit more time in the sun—25 minutes and 15 minutes respectively. From November to December, the UV risks lower again to moderate (3-4), allowing for 30 minutes. Visitors and residents should be especially cautious from March through September, particularly during peak summer months, by applying sunscreen, wearing protective clothing, and limiting sun exposure to mitigate the risk of UV-related health issues.
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 |
| Sendai | 3 | 4 | 7 | 8 | 10 | 10 | 11 | 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 |