Last updated: May 3, 2025
Understanding the UV Index is crucial for residents of Hayward, United States, where the climate can lead to varying levels of sun exposure throughout the year. Monitoring UV levels not only helps in preventing sunburn but also plays a significant role in maintaining long-term skin health. With typical peak UV readings, especially around midday, it's important to be aware of when to seek shade and apply sunscreen. Given Hayward's Dfb climate, where sunny days can be frequent, being UV-aware ensures you can enjoy the outdoors while protecting your skin from harm. Stay informed and stay safe under the sun!
As the day unfolds, the UV Index soars to its peak during the midday hours, reaching a maximum of 9 at 1:00 PM. Early risers will notice a milder UV level; at 7:00 AM, it's a mere 1, gradually climbing to 2 by 8:00 AM. As the sun climbs higher, the intensity intensifies — 3 by 9:00 AM, surging past 5 at 10:00 AM, and hitting 7 at 11:00 AM. The sun's power reaches its zenith at 12:00 PM, where it hits 8, before peaking at 1:00 PM. Following this peak, the UV Index starts to decline, with a gentle drop to 8 at 2:00 PM, further decreasing to 6 at 3:00 PM. By late afternoon, the readings dip to 3 at 5:00 PM, then fall to 2 by 6:00 PM, and finally retreat to 1 as daylight wanes at 7:00 PM. It's a compelling reminder to stay protected during the sun's most intense hours!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 2 | low | 45 min |
| 09:00 | 3 | moderate | 30 min |
| 10:00 | 5 | moderate | 30 min |
| 11:00 | 7 | high | 25 min |
| 12:00 | 8 | very high | 15 min |
| 13:00 | 9 | very high | 15 min |
| 14:00 | 8 | very high | 15 min |
| 15:00 | 6 | high | 25 min |
| 16:00 | 5 | moderate | 30 min |
| 17:00 | 3 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
As the seasons change, the UV Index experiences notable fluctuations, influencing both visitor and resident safety. January and December boast a low UV Index of 2, allowing for extended exposure times of 45 minutes without significant risk. However, as we move into spring with February and March, the UV Index rises to 4 and 5 respectively, indicating a moderate risk with a burn time of just 30 minutes. The high-risk months arrive in April through August, with peak values of 9 and 10 during May and June, categorizing the exposure as very high and shortening safe sun exposure to as little as 15 minutes. September sees a slight decrease to a high index of 7, while October and November return to moderate levels. Visitors and residents should take precautionary measures during the higher UV months by seeking shade, wearing protective clothing, and using sunscreen regularly to minimize skin damage.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Hayward | 2 | 4 | 5 | 7 | 9 | 10 | 9 | 8 | 7 | 5 | 3 | 2 |
| Chicago UVI | 3 | 4 | 6 | 8 | 9 | 10 | 10 | 9 | 8 | 6 | 4 | 2 |
| Brooklyn UVI | 3 | 5 | 6 | 8 | 10 | 10 | 9 | 9 | 8 | 6 | 4 | 2 |
| New York City UVI | 3 | 5 | 6 | 8 | 10 | 10 | 9 | 9 | 8 | 6 | 4 | 2 |
| Los Angeles UVI | 4 | 6 | 8 | 9 | 10 | 11 | 11 | 10 | 10 | 7 | 5 | 4 |
| Houston UVI | 5 | 8 | 9 | 11 | 11 | 12 | 12 | 11 | 10 | 9 | 7 | 5 |