Arctic climate is characterized by long winters and low city count. Though capitols are sometimes placed in this region, probably for strategic reasons of internal security.

Shorter winters then in the Arctic zone.

No snow anymore at all. Just 2 months of mud season and rain. The temperate and sub-tropical zone are the places where you'll find most towns.

Characterized by lower city count and the absence of any sort of mud or snow season. In the tropics you will also find a denser form of forest: Jungle. Agriculture in the tropical zone are rice padies or wadies. This landscape is equal to swamp. The combination of Jungle and wadies make the tropics hard going for any mechanized operation.

You'll also find deserts in either sub-tropical or tropical parts of the world. Deserts are characterized by absence of forests and swamps and towns. Though a capitol might show up now and then in the desert zone. Deserts are ideal country for panzer operations.

Regular summer landscapes.

Due to rain and melting snow operations are impaired. Mud gives mechanized (wheel&track) higher move costs. Rain and heavy clouds and fog make air movement impossible. Also mud hexes cost much more AP for the supplysystem, rail however keeps functioning unaffected, as do (sub)urban hexes. However for countryside and wilderness the mud and rain have quite some impact on maneuverability and the delivery of supplies. Mud is usually a pause in military operations.

Snow gives all troops increased auto-entrench. Also the extreme conditions that affect the troop outside of (sub)urban hexes cause 5% drop in readiness after supply consumption. This may not seem much but will require double the amount of supplies the next turn (if unit is set at 100% supply request).

Reasonable movement for motorized units. Low entrenchment options for infantry. Good terrain to attack on.

Reduce speed slightly and give a little extra entrenchment.

Hard to traverse for motorized units. Good entrenchment. Forests give attacking armor, artillery and aircraft a considerable penalty.

Impossible to enter for motorized units. Low entrenchment. Acts as plains when frozen. But movement for motorized units is still prohibited to avoid them getting stuck there when winter ends. Gives attacking armor a very considerable penalty in offense and defense. (if road through swamp armor can attack)

Hard to move into for all troops. Excellent entrenchment. Low mountains give attacking armor, artillery and aircraft a considerable penalty.

You cannot build roads through high mountains. Motorized units cannot move into them. They provide the best natural entrenchment available. Gives attacking artillery and aircraft a high penalty.

Urban terrain is immune from the negative effect of mud season on movement costs and also immune to the negative effect of readiness loss in the winter season. Urban is easy to move through, but has high entrenchment. Gives attacking armor, artillery and aircraft a considerable penalty.

The same as urban, but with lower entrenchment.

There are desert variants of a number of the above mentioned terrains. The desert variations, except for urban and suburban, have considerably lower entrenchment scores. This is due to lack of cover the arid climate causes.

There are major and minor rivers. They give negative combat modifiers to an attacker when attacking over a river hex border into another hex. The penalties are most heavy on tanks. Penalties do always apply, but they are lighter with minor rivers and also lighter if a bridge is still intact over the river. A river without a bridge will also cause heavy penalties on movement since a river crossing is never an easy feat.

There are railroads on the map and railroads can also be constructed with engineer units at a cost in raw materials. Railroads will make supply flow very far at very little AP cost. Also railroads will enable you to use trains in HQs to (strategicly) transfer without having to spend oil. Railroads also are considered to have a normal good road next to them and thus they provide quick lanes of movement to motorized units.

Fortifications impose extra penalties on artillery and armour attack (but not to air!). Fortresses impose even higher penalties on such attack. The fact that these modifiers come on top of landscape combat modifiers means that a fortress placed on for example a mountain hex is very well protected from most forms of attack.

Bridges can be constructed by engineers at a cost in raw materials.