car won't start in the cold, I already replaced the battery

so I parked my car outside the other day (it was hellaaaa cold) and it didn't
start the next day but I didn't need to go anywhere so I was like ok ill jump
start it tomorrow, so I tried that, didn't work, so then I took out my battery and
replaced it with a brand new one, and it still won't start. it sounds like it's
about to start but it just doesnt. its a 2008 Altima coupe 3.5SE. I replaced the
alternator prob 7 months ago, so it's not that. I had no engine lights on before
and still don't.