Understanding Spain’s Mediterranean Climate Zones
The Mediterranean Climate in Spain
The Mediterranean climate is the most extensive in Spain, encompassing the peninsular territory south of the oceanic climate zone, the Balearic Islands, Ceuta, and Melilla. Rainfall is low to moderate, irregular, and often stormy. The annual total is generally less than 800mm, with amounts between 500mm and 800mm considered moderate, and below 500mm considered low. Rainfall distribution is irregular, with dry summers due to the influence of the Azores High, which shifts northward during this season. Maximum rainfall occurs in autumn and spring, except in areas more exposed to the Atlantic, where it occurs in winter. Precipitation often falls as violent storms, which can severely erode soil in areas lacking vegetation. Temperatures vary with latitude and distance from the sea.
Maritime Mediterranean Climate
The maritime Mediterranean climate zone includes the Mediterranean coast of the peninsula (except the southeast) and the southwest Atlantic coast. On the southwest Atlantic coast, rainfall is more abundant due to the increased influence of Atlantic storms, especially those formed in the southwest peninsula and the Gulf of Cadiz, with a primary maximum in autumn-winter. Along the Mediterranean coast, rainfall is lower because Atlantic storms lose moisture crossing the peninsula and the mountain barriers parallel to the coast. The main rainfall maximum occurs in autumn due to storms caused by the contrast between the warm Mediterranean waters and the cooling land. These storms can also be caused by air masses from the European continent ascending the coastal mountain ranges, or by upper-level disturbances. Temperatures are moderate, with a thermal amplitude of 12-16°C due to the moderating influence of the Mediterranean Sea. Summers are hot (averaging 22°C or higher), and winters are mild (the coldest month does not fall below 10°C).
Continental Mediterranean Climate
The continental Mediterranean climate covers the interior of the peninsula, except for the central area of the Ebro Valley. Rainfall is low to moderate, between 300 and 800mm per year, with higher amounts in the western sector of the interior peninsula due to the more frequent passage of Atlantic storms. The main rainfall maximum is in winter. In the heart of Castile and the Ebro depression, rainfall is low due to the rain shadow effect of surrounding mountains. The rainfall maximum occurs during the equinoxes, especially in spring when winter anticyclones weaken. These anticyclones are formed by cold soil and can cause a secondary minimum in winter precipitation. Temperatures are characterized by a high thermal amplitude (above 16°C) due to the influence of continental air masses. Thermal variations allow for three subtypes:
- The northern sub-plateau and the highlands of Guadalajara, Teruel, and Cuenca have cool summers (less than 22°C) and cold winters (the coldest month does not fall below 6°C), with frequent frosts and fogs.
- The southern sub-plateau and the edges of the Ebro Valley have hot summers (greater than 22°C) and cold winters, although with a lower incidence of frost.
- Extremadura and inland Andalusia have hot summers and mild winters (the coldest month between 6 and 10°C).
Dry Mediterranean Climate (Steppe or Sub-Desert)
The dry Mediterranean climate, also known as steppe or sub-desert, covers the southeast peninsula and the central zone of the Ebro Valley. Rainfall is very low, between 150 and 300mm, giving it a steppe character. In the southeast, the aridity is due to the area being sheltered from Atlantic storms by the Andalusian mountain ranges, and the frequent arrival of dry air masses from Africa. Only storms entering through the narrow Strait of Alboran occasionally bring rain. In some areas, a true desert climate is reached (less than 150mm annual rainfall). In the middle of the Ebro Valley, the dryness is due to the rain shadow effect of the Iberian System, which acts as a barrier against Atlantic storms, and the Catalan coastal mountain range, which blocks the influence of the Mediterranean. Temperatures vary with latitude and distance from the sea. The warm steppe coast of the southeast has an annual average temperature around 17-18°C and mild winters (not falling below 10°C). The interior cold steppe of the southeast (east of Albacete) and the middle Ebro Valley have average annual temperatures below 17°C and mild or cold winters (6 to 10°C or below 6°C, respectively).