WEATHER EFFECTS
MUD CONDITIONS exist in the severe weather zone during M weather and in the moderate weather zone during W weather.
• Air units are grounded in the mud zone on a roll of 9-12 on two dice.
• Beakthrough and exploitation movement and attacks are not allowed in the mud zone.
• The movement allowances of land units (except HQs) are halved, with fractions rounded up.
• Attacks against hexes in the mud zone suffer a -1 penalty to the die roll.

WINTER CONDITIONS exist in the severe weather zone during W months.
• Air units are grounded in the winter zone on a roll of 7-12 on two dice.
• Exploitation movement and attacks are not allowed in the winter zone.
• The movement allowances of land units (except HQs) are halved, with fractions rounded up.
• Lake hexsides freeze and become passable to land units.
• Attacks across river and lake hexsides suffer a -1 die roll penalty instead of the usual -2 penalty.
• Naval interception die rolls have a -2 die roll modifier.
• U-boats that make sucessful attacks in the severe weather zone add +1 each to their EP damage die rolls.
• The harbour at Leningrad and Archangel freeze, making the ports unuseable.
• The cost of all offensives (icluding impromptu and combined offensives) doubles for every contry except the U.S.S.R.

TERRAIN EFFECTS SUMMARY
All terrain costs 1 movement point to enter (by land movement). Terrain affects land movement and combat as listed:.
CLEAR: Combat and movement occurs normally.
ROUGH: Attacks against units in rough hexes suffer a -1 die roll modifier.
MARSH: Armor units cannot move into, attack into, or project ZOC into marsh.
FOREST: Enemy ZOC does not affect supply lines or retreat routes in forest. A units in a forest hex in enemy ZOC can move 1 hex into another forest hex, even if both are in enemy ZOC.
CITY RESOURCE: Units trace supply to their home country city resource hexes. One extra land unit can stack in a city resource hex.
RIVERS, CANALS, FERRY-CROSSINGS: If the water barrier lies between all attacking units and the defendeng hex, the attack suffers a -2 die roll modifier.
IMPASSABLE HEXSIDES, LAKE HEXSIDES: Units cannot move, attack, or project ZOC across these hexsides.