Perhaps there may be two Moscow maps

An early one to represent the October rain & early snow melting.Armour would be slowed down because of the Mud.
Then when the ground froze finaly on 15-11-41, a winter map where armour could run faster.
I gues it will be one map though & it may be difficult to change ground unit speeds from one map to another.
There was also a lot of forest lined roads and tracks too.Should be interesting to see what comes out.