This problem is very common on battery powered bikes.
The first factor is the battery that must be mentioned. The normal operation of the battery requires a suitable working environment. The general optimum temperature is 25°C. When the temperature drops below 0°C, the drop in capacitance increases.
At the same time, the increase in the degree of adhesion of motor shaft lubricants in winter can also lead to a decrease in the efficiency of the motor and an increase in the amount of electricity used.
Besides, we often overlook the impact of electric vehicle drive controllers on power. When the controller and the motor are in the state of matching and mismatch, the working efficiency will differ by more than 30%. When the controller and the motor are mismatched, the motor and the electronic control will rapidly generate heat and turn the effective energy of the battery into useless heat energy, which can cause the loss of power.