Climatology of the Iberian Peninsula: Types and Characteristics
Key Parameters for Climate Analysis
Temperature Metrics
- Minimum recorded temperature and month of registration.
- Temperatures below zero (Winter conditions, leading to rain or snow).
- Maximum recorded temperature and month of registration.
- Thermal oscillation (amplitude): Maximum Mean Temperature (TM) minus Minimum Mean Temperature (Tm).
- Seasons definition: Summer (temperatures higher than 25 °C); Winter (temperatures lower than 0 °C).
Rainfall and Precipitation
- Total annual precipitation (in millimeters, mm).
- Precipitation regime: When does it rain? Aridity (periods of soil water deficit, exacerbated by evaporation).
- Seasons of highest rainfall.
Regional Climate Types
Atlantic Climate
Location
A stretch of the Iberian Peninsula (IP), including Galicia, Asturias, Cantabria, the Basque Country, Navarre, and the AHRANA valley.
Features
- Rainfall: Due to Atlantic depressions, rainfall is high (1000–2500 mm) and quite regular, averaging 150 days per year. Rains are scarce during the summer. Cloudiness and humidity are high.
- Temperatures: Annual averages are mild (11–15 °C) with low thermal amplitude.
- Wind: Winds usually blow from the west and are moderate, but occasionally cause storms.
Rivers
Abundant and regular flow. Due to the proximity of the mountains, they are short and have high erosive power.
Varieties
- Mountain Oceanic: Occurs in mountain areas (e.g., Cantabrian Mountains, Pyrenees). Temperatures are lower and precipitation is high.
- Oceanic Transition: Rainfall is lower, summers are drier, and winters are colder.
Vegetation
Temperate deciduous forests of beech and oak. This deciduous forest has often been substituted by pines and eucalyptus, forming the deteriorating heathland, a scrub dominated by heather and broom. This climate favors the formation of pastures and crops that require significant water, such as potatoes or corn.
Mediterranean Climate
Location
The southern part of the Iberian Peninsula, the Balearic Islands, much of Andalusia, and Extremadura.
Features
- The influence of subtropical anticyclones causes warm, dry, and arid conditions.
- In other seasons, mid-latitude depressions dominate, bringing rain, often torrential in autumn. Winters are mild.
- Winds from the east and wetter winds from the west raise temperatures.
Rivers
Rivers experience a long drought (low flow) in summer. Heavy autumn rains can rapidly increase the flow, potentially causing flooding.
Vegetation
The typical forest is the holm oak. Degradation leads to garrigue and steppe. Often substituted by pine. Cultivation is dominant in many areas.
Varieties
- Atlantic Influence: Evident where relief does not prevent the penetration of Atlantic depressions. Rainfall is abundant from October to May.
- Coastal Mediterranean: Occurs in mountains bordering the coast, receiving rains originating from the Mediterranean Sea.
- Arid/Semi-arid: Annual precipitation is rare (less than 400 mm). Occurs in the southeast (e.g., Almería, Murcia), showing marked aridity and a large water deficit.
Interior Mediterranean Climate (Continental)
Location
Almost the entirety of La Mancha, the Community of Madrid, and climatic transition zones.
Features
- Precipitation: Scarce throughout the year (325–550 mm), leading to corresponding summer aridity.
- Produces a strong thermal oscillation between summer and winter.
- Due to the lack of proximity to the sea, winter fog banks form, decreasing the hours of sunshine.
Rivers
Floods are irregular, occurring during periods of rain and snowmelt/thaw. Rivers experience low flow (estiatges) in summer.
Vegetation
- Mountain: Oak and pine forests.
- Plains: Shrubs and fields of grain.
Varieties
- Northern Plateau: Long and cold winters with dry, mild, and short summers (found in the sedimentary basin and the northern plateau of Spain surrounded by mountains).
- Interior Mountain: Found in the Iberian System, Central System, and the Toledo Mountains.
- Ebro Valley: Zones of short precipitation dominated by the Cierzo (a strong NW wind) which makes winters very cold and summers significantly cooler.
Note: Arid conditions are typically defined when annual rainfall is less than 250 mm.