Warm Temperate (Mid-Latitude) Climates according to Koeppen’s Classification
Warm temperate (mid-latitude) climates extend from 30° – 50° of latitude mainly on the eastern and western margins of continents. This climate generally has warm and humid summers with mild winters. During the winter, the main weather feature is the mid-latitude cyclone. Convective thunderstorms dominate summer months. Extreme summer aridity is caused by the sinking air of the subtropical highs and may exist for up to 5 months. Locations in North America are from Portland, Oregon to all of California.
These climates generally have warm summers with mild winters. They are grouped into four types:
(i) Humid subtropical, i.e. dry in winter, and hot in summer (CWA)
(ii) Mediterranean (Cs)
(iii) Humid subtropical, i.e. no dry season and mild winter (Cfa)
(iv) Marine west coast climate (Cfb).
Humid Subtropical Climate (CWA)
Humid subtropical climate occurs poleward of Tropic of Cancer and Capricorn, mainly in North Indian plains and South China interior plains. The climate is similar to Aw climate except that the temperature in winter is warm.
Mediterranean Climate (Cs)
As the name suggests, Mediterranean climate occurs around Mediterranean sea, along with the west coast of continents in subtropical latitudes between 30° – 40° latitudes e.g. — Central California, Central Chile, along with the coast in southeastern and southwestern Australia. These areas come under the influence of subtropical high in summer and westerly wind in winter. Hence, the climate is characterized by hot, dry summer and mild, rainy winter. The monthly average temperature in summer is around 25° C and in winter below 10°C. The annual precipitation ranges between 35 – 90 cm.
Humid Subtropical (Cfa) Climate
Humid subtropical climate lies on the eastern parts of the continent in subtropical latitudes. In this region, the air masses are generally unstable and cause rainfall throughout the year. They occur in eastern United States of America, southern and eastern China, southern Japan, northeastern Argentina, coastal South Africa and eastern coast of Australia. The annual averages of precipitation vary from 75-150 cm. Thunderstorms in summer and frontal precipitations in winter are common. Mean monthly temperature in summer is around 27°C, and in winter it varies from 5°-12° C. The daily range of temperature is small.
Marine West Coast Climate (Cfb)
Marine west coast climate is located poleward from the Mediterranean climate on the west coast of the continents. The main areas are; Northwestern Europe, west coast of North America, north of California, southern Chile, southeastern Australia, and New Zealand. Due to marine influence, the temperature is moderate and in winter, it is warmer than for its latitude. The mean temperature in summer months ranges from 15°-20°C and in winter 4°-10°C. The annual and daily ranges of temperature are small. Precipitation occurs throughout the year. Precipitation varies greatly from 50 – 250 cm.