Last updated: July 2, 2025
Understanding the UV Index is crucial for residents and visitors in Bilbao, Spain, where the climate tends to be mild yet can lead to significant UV exposure. Awareness of UV levels plays a vital role in preventing sunburn and maintaining skin health, especially during the sunniest hours of the day when the index peaks at 10 between 2 PM and 3 PM. With its temperate maritime climate, Bilbao offers a mix of sunshine and overcast days, but don't let the clouds deceive you—safe sun practices are essential year-round to protect against potential skin damage and long-term health risks.
The UV Index for the day starts off mild, with values of 1 at both 7:00 and 8:00 AM, indicating that sun protection is not yet a priority. As the morning progresses, the index gradually rises, reaching 2 by 9:00 AM and 3 by 10:00 AM. The real intensity kicks in around 11:00 AM, where the UV Index escalates to 5, marking the beginning of elevated sun exposure. By noon, the index spikes to 7, and peaks at 10 by 2:00 PM, signaling a period of high risk for harm from unprotected sun exposure. As the afternoon shifts, values begin to taper off, dropping to 6 by 5:00 PM, then easing to 4 by 6:00 PM, and finally closing the day at 2 by 7:00 PM. It's a clear reminder to stay protected during peak hours!
| Time | UVI | Category | Time to Burn |
|---|---|---|---|
| 07:00 | 1 | low | 45 min |
| 08:00 | 1 | low | 45 min |
| 09:00 | 2 | low | 45 min |
| 10:00 | 3 | moderate | 30 min |
| 11:00 | 5 | moderate | 30 min |
| 12:00 | 7 | high | 25 min |
| 13:00 | 9 | very high | 15 min |
| 14:00 | 10 | very high | 15 min |
| 15:00 | 9 | very high | 15 min |
| 16:00 | 8 | very high | 15 min |
| 17:00 | 6 | high | 25 min |
| 18:00 | 4 | moderate | 30 min |
| 19:00 | 2 | low | 45 min |
Throughout the year, seasonal changes in UV exposure highlight significant fluctuations in the UV Index. The months of May through August are particularly high-risk, with UV Index values reaching a peak of 10, indicating very high exposure and a burn time of only 15 minutes. Visitors and residents should remain vigilant during these months, employing protective measures such as sunscreen and clothing, especially between 10 AM and 4 PM when UV exposure is strongest. March and April also show increased risk with UV Index values of 6 and 7 respectively. Conversely, January and December present lower risk levels, with UV Index values of 2 indicating low exposure and longer potential burn times of 45 minutes. It is essential to monitor UV levels year-round and adjust sun protection strategies accordingly to ensure safety.
UV Risk Categories
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Barcelona UVI | 3 | 4 | 5 | 7 | 8 | 10 | 10 | 9 | 7 | 6 | 3 | 2 |
| Bilbao | 2 | 4 | 6 | 7 | 9 | 10 | 10 | 9 | 7 | 5 | 3 | 2 |
| Zaragoza UVI | 3 | 4 | 6 | 8 | 9 | 11 | 11 | 9 | 8 | 6 | 3 | 2 |
| Valencia UVI | 3 | 4 | 6 | 8 | 9 | 11 | 10 | 9 | 8 | 6 | 4 | 3 |
| Madrid UVI | 3 | 4 | 6 | 8 | 10 | 11 | 11 | 9 | 8 | 6 | 4 | 3 |
| Sevilla UVI | 3 | 5 | 7 | 9 | 10 | 11 | 10 | 10 | 9 | 7 | 4 | 3 |