Cold is the electric truck’s tax collector, and it is not negotiable. Scandinavian and Danish fleet measurements converge on a 20–30% winter range penalty in sustained sub-zero operation — from battery chemistry slowing, cabin heating loads on a 40-tonne duty cycle, and snow/rolling resistance. A tractor specced at its limit in October becomes a logistics problem in January.

What actually drives the penalty. Three mechanisms, in descending order for heavy trucks: thermal management (heating a large cabin and keeping the pack in its efficient window draws several kW continuously — meaningful against a 500 km day’s margin); reduced regenerative efficiency and charging speed in cold packs (a cold battery accepts charge slower — winter charging stops run longer); and aerodynamics/rolling resistance from winter conditions. The chemistry itself matters less than the heat budget.

The operational playbook. (1) Size for January, not for the average: spec battery and charging against the worst month of your duty cycle, or accept a winter route modification in writing. (2) Precondition everything: schedule pack and cabin preheating on depot power before departure — energy drawn from the charger is energy not drawn from the pack. (3) Charge warm: plan fast-charging stops immediately after driving segments, while the pack is at temperature. (4) Heat-pump cabins and heated seats over resistive cabin heating where optioned. (5) Treat winter tyres’ consumption penalty as a known constant, not a surprise.

The planning number. For BE/NL/DE corridor duty, a 15–20% winter margin suffices in most years; for Nordic or Alpine routes, plan 25–30% and validate with a winter pilot before committing a fleet. Any vendor TCO that shows you annual-average consumption without a winter line is selling, not advising. Our field-test programme includes a winter cycle for exactly this reason — measured numbers, on real routes, in February.

WattTonne’s read. Winter is the easiest objection to answer honestly and the most expensive to answer wrong. Fleets that pilot through one winter before scaling replace anxiety with data; those that scale on summer numbers get a January surprise.