Last updated: July 2, 2025
In Johnston, United Kingdom, staying vigilant about the UV Index is crucial for protecting your skin and overall health. Understanding UV levels helps to prevent sunburn and reduces the long-term risk of skin damage, especially during sunny days. With its temperate maritime climate (Cfb), Johnston experiences variable UV exposure that can peak significantly during midday hours—often reaching levels of 8 between 12 PM and 2 PM. By keeping an eye on the UV Index, residents and visitors can enjoy the outdoor beauty of Johnston while effectively safeguarding their skin against harmful radiation.
The UV Index fluctuates throughout the day, reaching its peak of 8 between noon and 2 PM. Early risers will notice a gentle start, with levels at just 1 at 7 AM. As the sun climbs higher, the index rises steadily, hitting 5 by 10 AM and 6 by 11 AM. By 12 PM, the intensity peaks, prompting caution for those outdoors. After this midday surge, the index begins a gradual decline, dropping to 7 at 3 PM, and falling further to 4 by 5 PM. As evening approaches, UV levels decrease significantly, resting at 1 by 7 PM. It’s a clear reminder to stay sun-safe during those peak 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 | 6 | high | 25 min |
| 12:00 | 8 | very high | 15 min |
| 13:00 | 8 | very high | 15 min |
| 14:00 | 8 | very high | 15 min |
| 15:00 | 7 | high | 25 min |
| 16:00 | 6 | high | 25 min |
| 17:00 | 4 | moderate | 30 min |
| 18:00 | 2 | low | 45 min |
| 19:00 | 1 | low | 45 min |
Throughout the year, the UV Index exhibits notable seasonal fluctuations, significantly influencing exposure risks for both residents and visitors. The high-risk months for UV exposure are typically from April to August, where the index peaks at 8 during June and July, indicating very high exposure levels with a burn time of just 15 minutes. March marks the transition into the moderate category with an index of 4, while from October to February, the risk decreases to the low category, allowing for extended burn times of 45 minutes in winter months. Visitors and residents are strongly advised to take precautionary measures when UV levels are moderate or higher, particularly by seeking shade, wearing protective clothing, and applying sunscreen regularly during the higher index months to safeguard against harmful sun exposure.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Liverpool UVI | 1 | 2 | 3 | 5 | 7 | 8 | 8 | 7 | 5 | 3 | 2 | 1 |
| Sheffield UVI | 1 | 2 | 4 | 5 | 7 | 8 | 8 | 7 | 5 | 4 | 2 | 1 |
| Birmingham UVI | 1 | 2 | 4 | 5 | 7 | 8 | 8 | 7 | 6 | 4 | 2 | 1 |
| London UVI | 1 | 2 | 4 | 5 | 7 | 8 | 8 | 7 | 6 | 4 | 2 | 1 |
| Bristol UVI | 1 | 2 | 4 | 5 | 7 | 8 | 8 | 7 | 6 | 4 | 2 | 1 |
| Johnston | 1 | 2 | 4 | 6 | 7 | 8 | 8 | 7 | 6 | 4 | 2 | 1 |