Euskal Herria Climate Zones: Mountain, Atlantic, and Continental

Climatic Diversity in Euskal Herria

Due to various factors—including latitude, typical weather situations arising between southwestern Europe and the Atlantic Ocean, the impact of the Azores anticyclone, terrain, and influence on sea and air masses arriving from the Atlantic—Euskal Herria exhibits three main climates: Mountain, Atlantic (or Mediterranean-oceanic), and Continental. Transitional climates also exist among these types.

Mountain Climate

The Mountain Climate, also called subalpine, is found in the eastern Pyrenees of Euskal Herria, specifically south of Nafarroa Beherea and Soule, and in northern and northwestern Navarre.

• The elevation of the Pyrenees decisively marks this climate's characteristics.
• Average temperatures are low (around 10 ºC to 12 ºC), particularly cold in winter.
• Rainfall is abundant (over 1,500 mm annually, sometimes exceeding 2,000 mm).
• Above 1,500 m, precipitation falls as snow between autumn and spring, leaving the highest peaks snow-covered for several months.

Atlantic Climate

The Atlantic Climate covers the northern half of Euskal Herria, typical for all of Bizkaia, Gipuzkoa, Lapurdi, and northern areas of Aruba, northwestern Navarre, and central and northern Nafarroa Beherea and Soule.

Characteristics:

This is a typical humid temperate climate without a dry season.

• Summers: Warm (mean temperature 20 ºC to 22 ºC).
• Winters: Mild (mean temperature 7 ºC to 8 ºC).
• The average annual temperature is around 12 ºC, with little temperature fluctuation (between 10 ºC and 13 ºC).
• Rainfall (between 1,000 to 1,500 mm annually) is spread throughout the year, though it is highest in spring and autumn.
• Snowfall occurs occasionally in winter but rarely persists except in the highest mountains.
• Closer to the sea, ocean features are more pronounced, resulting in consistently milder temperatures and lower thermal oscillation along the coast.

Mediterranean-Continental Climate

The Mediterranean-Continental Climate almost coincides with the Mediterranean river basin, extending through southern Araba and central and southern Navarre.

Key Features:

• Summers: Hot (about 22 ºC).
• Winters: Cold, with significant temperature variations (over 15 ºC).
• Annual rainfall does not exceed 1,000 mm; in some areas, it does not reach 500 mm, as moist air masses from the Cantabrian Sea arrive significantly weakened after crossing mountain barriers.
• As one moves south, there is a high rate of clear days per year.
• Frosts occasionally occur, proving very harmful to agriculture.
• A cold, dry north wind, called the Cierzo (implied context, often associated with this climate type), can arise.