Last updated: August 1, 2025
In Ryotsu-minato, Japan, being aware of the UV Index is crucial for safeguarding your skin against harmful UV radiation. Understanding these UV levels helps in preventing sunburns and reducing the long-term risks of skin damage. With a Cfa climate, Ryotsu-minato experiences varying UV exposure throughout the day, peaking at 10 between 11:00 AM and 12:00 PM. As the sun's rays intensify, it's essential to take necessary precautions during these hours to protect your skin health and enjoy the beautiful outdoors safely.
As the sun rises, the UV Index begins to climb steadily. At 7:00 AM, it registers a mild level of 2, but by 8:00 AM, it escalates to 4, indicating the start of a more intense sun exposure. The peak occurs at 11:00 AM and 12:00 PM, where it reaches a soaring 10, alerting everyone to take necessary precautions. After midday, the intensity starts to wane: it gently drops to 9 at 1:00 PM and gradually decreases to 5 by 3:00 PM. As the afternoon fades into evening, the UV Index dwindles to 3 at 4:00 PM and finally settles at 1 by 5:00 PM, bringing a close to the day's sun exposure risks. As night approaches, the UV Index drops to 0 after 7:00 PM, signifying a safe respite from the sun’s harsh rays.
| 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 | 10 | very high | 15 min |
| 12:00 | 11 | extreme | 10 min |
| 13:00 | 10 | very high | 15 min |
| 14:00 | 8 | very high | 15 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 |
| Ryotsu-minato | 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 |