Temperate climates are where most of Earth’s population lives, though that’s partly because much of our land is there. These climates have an average monthly temperature above 10° C (50° F) in their warmest months and an average monthly temperature above −3° C (27° F) in their coldest months. Some have dry winters, dry summers, or significant precipitation throughout the year.
There are several versions of temperate climates, discussed next.
Dry summer climates, also known as a Mediterranean climate on Earth, usually occur on the western sides of continents between the latitudes of 30° and 50°. Summers are hot and dry except in coastal areas, where summers are milder due to nearby cold ocean currents that may bring fog but prevent rain. Winters are mild with rainy weather. Most rain is during winter, hence the name “dry summer.” This climate is found around the Mediterranean and much of California.
Warm temperate climates usually occur on the eastern coasts and sides of continents, from 25° to 45° latitude, such as the southeastern United States. Moisture from the tropics causes air to be warm and wet. More rainfall occurs in summer than in winter. The air flow out of the tropics brings warm, moist air to the southeast of continents. This flow is often what brings the frequent but short-lived summer thundershowers typical of subtropical east-coast climates.
These climates usually occur on the western sides of continents between the latitudes of 45° and 60° and immediately poleward of dry summer climates (such as north of them in the northern hemisphere). This includes the Pacific Northwest and New Zealand. They have changeable, often overcast weather. Summers are cool due to cool ocean currents, but winters are milder than other climates in similar latitudes, and very cloudy. This climate can also be found at higher elevations in latitudes that would otherwise be subtropical or temperate. These high-altitude climates are called oceanic even if they’re not near an ocean.
Temperate Highland Tropical with Dry Winters
This is characteristic of the highlands in the tropics. Winters are dry, unlike other tropical areas. Summers can be very rainy.
Maritime Subarctic or Subpolar Oceanic
These climates occur poleward of the maritime temperate climates, such as Iceland. They happen on narrow coastal strips of land on the western poleward margins of the continents or to islands off such coasts. There is very little precipitation and temperature variations are extreme between winter, at -40° C (-40° F), and summer, up to 30° C (86° F). The ground is frozen in winter to depths of several feet.
Dry Summer Maritime Subalpine
This climate is very rare and only exists at very high elevations where the ocean influence keeps the temperature from going below -3 C° (26° F). As a world builder, we can largely ignore this unless we need it.