Last updated: June 2, 2025
Understanding the UV Index is crucial for residents of Westford, United States, where the climate showcases a humid continental zone (Dfb) that can lead to significant sun exposure throughout the year. This knowledge is vital in safeguarding against harmful UV radiation, helping to prevent sunburn and promote overall skin health. With UV levels peaking at a striking 10 around midday, awareness of fluctuating UV Index readings is essential for making informed outdoor plans and protecting your skin from potential risks. Whether basking in the summer sun or enjoying a crisp fall day, knowing when to take precautions can make all the difference in Westford's vibrant outdoor lifestyle.
The hourly UV Index data reveals a dynamic shift in sun intensity throughout the day, starting from a gentle 1 at 07:00, ideal for morning strolls. As the sun rises higher, the index escalates, peaking at a potent 10 between 12:00 and 13:00. This mid-day surge emphasizes the need for sunscreen and protective gear, as the risk of harm from UV rays increases significantly. By 15:00, the index begins to decline, settling at 7 before tapering off further to a mere 1 by 19:00, signaling a safe reprieve for evening outdoor activities. Stay aware and protect your skin during those peak hours!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 2 | low | 45 min |
| 09:00 | 4 | moderate | 30 min |
| 10:00 | 6 | high | 25 min |
| 11:00 | 8 | very high | 15 min |
| 12:00 | 10 | very high | 15 min |
| 13:00 | 10 | very high | 15 min |
| 14:00 | 9 | very high | 15 min |
| 15:00 | 7 | 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 |
The UV Index exhibits notable seasonal changes throughout the year, with high-risk months primarily occurring from April to August, when the index reaches very high levels (8-10) and a burn time of just 15 minutes is recommended. Specifically, April through July are critical periods, with May and June experiencing the highest values. During these months, it is essential for visitors and residents to take precautions such as wearing sunscreen, protective clothing, and sunglasses, and seeking shade during peak sun hours. Conversely, January and December present lower risks with a UV Index of 2-3, allowing for more extended sun exposure of up to 45 minutes and only moderate protection needed. Overall, staying informed of the UV Index can help ensure safety and enjoyment while outdoors year-round.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Westford | 3 | 5 | 6 | 8 | 9 | 10 | 9 | 9 | 7 | 6 | 4 | 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 |