The setting stretches from the arctic to the antarctic. The basic climactic zones are shown on map #1. The following descriptions are taken from the Ruin’s of Empire Regent’s Guide available on the Twilight Peaks forum, or here.
Arctic: Arctic climate is only found in extreme latitudes. Mountains, glacier and barren are common terrain types. Winter weather is common throughout the year. Warfare is near-impossible. It is generally unsuitable for habitation thanks to a combination of bad terrain and a big negative modifier to maximum province level.
Subarctic: Sub-arctic climate is found in high latitudes and in large alpine areas. Tundra, mountains and glaciers are common, as well as some forest, woods and moors. Weather is often harsh, with long and bitter winters. Warfare is only possible during the brief summer. It is not well suited for habitation.
Temperate (cool): Cold temperate climate has much in common with sub-arctic climate during winter and temperate climate in summer. Forest, woods and moors are common terrain types. To wage war during winter is nearly impossible. It is suitable for habitation.
Temperate: Temperate climate is found throughout much of Cerilia. It contains are wide variety of terrain types. Weather patterns are generally benign, with few extremes. Warfare is usually conducted during the summer. It is well suited for habitation.
Temperate (warm): Hot temperate climate is generally the most hospitable of all climate zones. It contains are wide variety of terrain types. Weather patterns are benign, with very mild winters, but summers can be quite hot. Warfare is possible throughout the year, but most common in the autumn because of the summer heat. It is very well suited for habitation.
Sub-tropical: Sub-tropical climate is generally hot and dry. Steppe and desert terrain is common. Extreme heat and lack of water during the summer makes warfare impractical during this period, except for troops used to these conditions. It is suitable for habitation.
Tropical: Tropical climate is generally hot and moist. Swamp and jungle are common terrain types. There weather is quite extreme throughout the year, with warfare most common during dry periods. It is fairly well suited for habitation.
The effective climate of a given region may differ from that of the general zone into which it falls, and is
mostly is dependent on the ocean currents. Warm currents will make the effective climate one step warmer and a cold current will make it one step cooler. In addition altitude will also affect the effective climate, with higher altitudes dropping the effective climate one step cooler.
The map shows the the ocean currents, with warm currents in red and cold currents in blue. The effective climate is shown using the same colours as in the general climate zone map:
- White = Arctic
- Gray = Subarctic
- Pale green = Cool Temperate
- Medium Green = Temperate
- Dark Green = Warm Temperate
- Yellow = Sub-Tropical
- Orange = Tropical
The prevailing winds have a smaller effect on the climate, but they do influence the vegetation type of an area. The prevailing winds and the way they influenced the ground cover can be seen on the following map.