The temperatures are mild in December in Béarn and Bigorre. It was around 20 degrees this Thursday, December 30. “This is not unusual. We often have Christmases on the balcony. This is due to the natural variability of the climate,” Francis Morisset, climatologist for the Pyrénées-Atlantiques and consulting forecaster for western New Aquitaine, told Météo-France. He notes temperature records at Navarrenx: “We recorded 22.2 ° on December 22, 22.7 ° on 23 and 22.6 ° on 29. Otherwise we have not broken a record for the moment”. In Pau, for example, it was 27.2 ° on December 4, 1985 against 19 ° on December 30, and the normal for the season was 11.6 °.
It was hotter in December 2015
According to the forecaster, “December 2015 presented a positive anomaly of 4.22 °. This year, we are far behind, with a positive anomaly of almost 2 °”. On the other hand, when he observed the temperatures of the last decade, that is to say between December 20 and 30, he noticed that it was 6 degrees higher than seasonal norms.
Francis Morisset believes that “What is a little more exceptional is that we don’t really have a southerly wind yet. It has not yet risen. Because there is what we call the foehn effect : when the wind coming from the south is compressed by the Pyrenees, it dries up and warms up. For example, if you compress air in your bicycle pump you heat it up. However, at the moment this is not the case“.
“Temperatures of remarkable mildness in the mountains”
Thomas Bouffon, forecaster at the Pyrenees meteorological center in Tarbes partly makes the same observation: “For the moment, the temperatures are not exceptional. On the other hand, we are going to monitor the temperatures of January 1 since we could approach the temperature records for a month of December with 25 ° in the west of Béarn “. He draws two other lessons: “We have remarkably mild temperatures in the mountains. On Thursday, it was 11 degrees at Soum Couy at 2800 meters, almost 8 ° at Pic du Midi de Bigorre. The minimum temperature [au lever du jour] the highest at the midday peak is 4.4 degrees, there we exceed 6 ° “. It is for him, one of the effects of climate change.
The forecaster also notes that the snow cover remains in excess from an altitude of 1300 meters. “It is a spring-like snowpack which freezes again very well at night and remains hard. Therefore, hikers must remain vigilant against the risk of slips when the air temperatures are mild.”