Last updated: August 1, 2025
In Greenfield, United States, being aware of the UV Index is crucial for safeguarding your skin health and preventing painful sunburns. Understanding the UV levels throughout the day helps residents make informed decisions about sun exposure, especially during peak hours when the index reaches a maximum of 10 around noon. With Greenfield's Dfa climate characterized by warm summers, the risk of excessive UV exposure can be significant. By keeping an eye on the UV Index, you can enjoy the outdoors while protecting yourself from harmful rays.
Throughout the day, the UV Index exhibits a remarkable rise, peaking at 10 between 12:00 PM and 2:00 PM, indicating a high risk of harm from unprotected sun exposure. Starting the morning at a mere 1 at 7:00 AM, the index steadily climbs as the sun ascends, hitting 5 by 10:00 AM and rapidly accelerating to 8 by 11:00 AM. After reaching its zenith at noon, the readings gradually decline through the afternoon, dropping to 4 by 5:00 PM and falling further to 1 by 7:00 PM. It's clear that careful sun protection is essential during the midday hours when the sun's strength is at its most intense.
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 1 | low | 45 min |
| 09:00 | 3 | moderate | 30 min |
| 10:00 | 4 | 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 | 9 | very high | 15 min |
| 15:00 | 8 | very high | 15 min |
| 16:00 | 6 | high | 25 min |
| 17:00 | 3 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
The seasonal UV changes reveal a significant increase in ultraviolet exposure from winter to summer, peaking in June with an extreme UV Index of 11 and a burn time of just 10 minutes. High-risk months include April to August, where residents and visitors should take extra precautions due to very high UV levels. Specifically, in April (UV Index 8) and May (UV Index 10), the burn time decreases sharply to 15 minutes, while June remains critical with its extreme rating. As summer transitions to autumn, UV exposure diminishes, lowering to a high level in October (UV Index 6). To protect against skin damage, it is advisable to wear sun protection, such as sunscreen and UV-blocking clothing, especially during peak hours in these high-risk months.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 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 |
| Greenfield | 3 | 5 | 6 | 8 | 10 | 11 | 10 | 9 | 8 | 6 | 4 | 3 |
| 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 |