Last updated: June 2, 2025
In Foster, United States, staying informed about the UV Index is crucial for protecting your skin and overall health. Understanding these UV levels can mean the difference between a day of fun in the sun and painful sunburns. With a climate characterized as Cfb, Foster experiences unique exposure risks throughout the day, particularly during peak hours when the UV Index can soar to a maximum of 10 around midday. By keeping an eye on the UV forecast, you can enjoy the beautiful outdoors while safeguarding your skin from harmful radiation.
As the sun rises, the UV Index starts its ascent, with a gentle 1 at 07:00. By 08:00, it begins to climb, reaching 2, signaling a reminder to take care. The real intensity kicks in at 10:00, where the index peaks at 6, escalating to a scorching 9 by noon. The hottest moment arrives at 13:00, showcasing a dramatic 10—a level that demands serious sun protection. Although the UV level begins to drop after this peak, it remains notable; at 14:00, it settles at 9, then declines gently, hitting 3 by 17:00. As daylight fades towards the evening, it tapers off to 2 at 18:00 and finally returns to a safe 1 by 19:00. It's a vivid reminder of the sun's power throughout the day!
| 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 | 9 | 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 |
As the seasons change, the UV Index exhibits significant fluctuations, indicating varying levels of sun exposure risk. From January to March, the UV Index starts off in the moderate range (3-6), suggesting a burn time of 30 minutes in January and February, but decreases to 25 minutes in March. The high-risk months emerge from April to September, where the Index rises dramatically to the very high range (8-10), with a critical burn time dropping as low as 15 minutes in April, May, June, July, August, and September. October sees a decline back to a high UV Index (6), allowing for 25 minutes of exposure before burning, while November and December move back into moderate and low categories (4 and 2, respectively) with more forgiving burn times of 30 minutes and 45 minutes. Visitors and residents are strongly advised to take precautions during the high-risk months by wearing sunscreen, protective clothing, and seeking shade, particularly when the UV Index is at its peak in the summer months.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Foster | 3 | 5 | 6 | 8 | 9 | 10 | 9 | 9 | 8 | 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 |