On the Eastern Battlefield, the time suitable for warfare is actually quite limited. Spring and autumn bring melting snow and rain, leaving mud pits deep enough to reach above a carriage's roof everywhere, and the harsh winter restricts troop movements. The truly optimal periods for marching and combat are summer and the brief stretch after the frost sets in but before the intense cold arrives.
The Duchy has confined its war cycle against Lapland to a half-month after the frost period, clearly aiming for a swift campaign. The goal is to rapidly occupy the target area, then leverage the severe winter to hinder Lapland's counterattacks and any external intervention. This strategy intentionally uses the established facts to gain advantages in subsequent negotiations.
Although this decision stems from political calculations and objective conditions, it indeed holds a certain military rationale.
