The characteristics of the Picos de Europa mean that there can be a stark change in weather from the valley bottoms to the top of the mountains where rain, snow, or frost is possible. One characteristic is their location on the northern side of the Cantabrian Mountains and their proximity to the sea, and further one is their altitude. Due to this, the predominant weather in the area is Cantabrian, with high levels of humidity and less sun. The low temperature average in the valleys is 4.3ºC, and the high temperature average is 22.3ºC. In the interior of the massif, minimum temperatures remain below zero from December to May. The region of Liébana is protected between the Cantabrian Mountains and the Picos, and therefore has more benign weather being milder and sunnier than other areas.
The predominant winds are NW Atlantic ones, that tend to bring rain and snow. The south-west wind blows in autumn, and clears the atmosphere. This is when some of the most amazing views can be seen in the Picos.
Precipitation levels are on average about 1 900 mm/year, but are higher in the Western Massif, where there are more heavy snowfalls. There’s an average of 193 days per year with rain, that is 53% of the year. Snow completely covers the massifs from December to May and snow/ice pockets can remain in sheltered places, even in summer. If snowfalls are intense in areas with steep slopes, there is a risk of avalanches.
The most characteristic weather phenomenon in the Picos is the mist or the “encainada”, as shepherds call it. It is very common in summer, which is why taking precautions in such a laberynth-type terrain is so important. It is not rare to have a splendid sun shining in the high areas of the Massifs while the mist is still in the valleys, covering them until well past midday
The following websites are the best to check weather in the Picos, but you must bear in mind that these mountains have two very different mountain aspects and many valleys, which is why a general weather forecast might not be accurate in all the areas.