That's all true, but given that both parties were evenly matched before picking winter to do battle required something to tip the advantage to the attacker who picked that time because they had a solution to the problem of dealing with chapped hands, which in the age of manual combat may well have been of such importance that the outcome was all but certain.
Asterix joke: "The Romans, upon learning that the English requested a daily ceasefire from 2pm to 4pm because they were having tea decided to attack only between 2pm and 4pm". Obviously, that's fictional but you get the idea.
Before the final battle when all seems to be lost because the barrel of magic potion was sunk in the river Asterix announces that they have the makings of the magic potion (pulling some herbs out of his pocket) - synopsis from link above:
"Finally reaching the independent village, Asterix eases the Britons' disappointment by claiming he carries herbs to remake the potion; these are later revealed to be tea. With a psychological boost, the village prevails against the Romans. Asterix and Obelix return home to the inevitable feast. The Britons like the tea so much, they proclaim it shall be their national drink."
Ah yes, of course! The tea was revealed on the last page only. My memory isn't entirely bit-rot proof and it's been a good 47 years since I last read that particular story.
Wait, there's an ongoing alternate history French comic that's been published since 1959 about warriors from Gaul fighting the Roman Republic under Caesar?
I admit, retconning your arch-foe's national non-alcoholic drink of choice is fairly grand, but I feel like you buried the lede there.
Asterix joke: "The Romans, upon learning that the English requested a daily ceasefire from 2pm to 4pm because they were having tea decided to attack only between 2pm and 4pm". Obviously, that's fictional but you get the idea.