What happens inside the battery?
Temperature can affect performance
Inside a lithium battery there is a chemical reaction going on which enables the battery to be charged and discharged. When the battery is exposed to freezing temperatures the inner resistance rises dramatically which causes the chemical reaction to slow down, making the battery work less efficient. This means that the battery capacity drops and your lithium battery powered devices will run out of power quicker.
You see this reaction with electric cars which looses a big chunk of their range in the winter time.
This does not mean that you can’t use your lithium powered Suprabeam lights in the cold, because you definitely can! But you must expect that the performance and battery life is going to be affected by the temperature.