I'd wait. I HAD to go out yesterday and the battery died even though I had driven it pretty far. The alternator puts out like a champ and the thing still died.

When it's warmer the alternator can better keep up with the excessive draw caused by the cold. I had no other option but didn't realize my battery was "weak". It was working fine so long as the weather wasn't this cold, but then it was like... "Yeah, I ain't doin' this, man." RIP little battery... RIP.