Last updated: August 1, 2025
Understanding the UV Index is crucial for residents and visitors in Itayanagi, Japan, where the combination of a humid subtropical climate (Cfa) and high sun exposure can pose significant risks to skin health. During peak sun hours, particularly between 10 AM and 2 PM, UV levels can soar to 10, indicating a very high risk of harm from unprotected sun exposure. Being aware of these levels helps in preventing sunburn and long-term skin damage. With Itayanagi's typical weather conditions facilitating increased UV radiation, staying informed about the local UV Index not only enhances your outdoor enjoyment but also ensures you take the necessary precautions to protect your skin.
During the early morning hours, the UV Index starts off mild, peaking at 3 by 7:00 AM. As the sun climbs higher, the intensity increases, hitting 4 by 8:00 AM and dramatically soaring to a peak of 10 at both 11:00 AM and 12:00 PM. This high level indicates a very high risk for harm from unprotected sun exposure. The afternoon brings a gradual decline, with the index dropping to 9 at 1:00 PM before easing down to 5 by 3:00 PM. As the sun sets, the UV Index gently recedes to 1 by 5:00 PM, ultimately falling to 0 by 7:00 PM, signaling a safe end to UV exposure for the day. Stay protected when the index is high, and enjoy the sun responsibly!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 2 | low | 45 min |
| 08:00 | 4 | moderate | 30 min |
| 09:00 | 7 | high | 25 min |
| 10:00 | 9 | very high | 15 min |
| 11:00 | 11 | extreme | 10 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 |
Throughout the year, UV levels fluctuate significantly, with higher levels observed from March to September. The peak risk months are June, July, and August, where the UV Index reaches as high as 11, categorized as extreme, boasting a burn time of just 10 minutes. In spring, particularly April and May, the UV exposure escalates to very high levels (Index of 8-9), requiring heightened awareness. From October to March, UV Index values decrease, though residents and visitors should still take precautions in March (Index of 6) and October (Index of 6) due to higher risk levels. As a general guideline, it’s advisable to wear sunscreen and protective clothing, especially during peak hours, from March to August, to minimize sun exposure and reduce the risk of skin damage.
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 |
| Itayanagi | 3 | 4 | 6 | 8 | 9 | 10 | 10 | 11 | 8 | 6 | 4 | 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 |