The chemical reaction that allows car batteries to discharge amps slows down with lower temps, laws of physics suck almost as much as the laws of gravity, almost
At 32degF car battery loses 30% of its amp capacity, at 0degF 50%
And to add to the burden, engine takes a few more amps to start when temps drop.
If your battery is 3 years or older a cold snap might leave you looking for a jump.
Car batteries have 6 cells, when new they can hold 2.14 volts each.
As they are discharged and recharged they start to hold less.
If you measure voltage after battery sits a few hours you can get an idea of its age.
New battery is 12.8volts and has 100% capacity
2-3 years old 12.6volts 75%
4-5 years old 12.4volts 50%
5 years+ 12.2volts 25%