Other common causes include a leaky injector causing a fuel-wet cylinder after sitting that has to clear out, or a sticky IAC valve causing an incorrect cold start mixture, vacuum leaks that cause the mix to be too lean for cold run, and a throttle plate that's not fully closing due to deposits, which undermines the IAC's ability to control the mix, coolant temp sensor gone bad, making the ECM command wrong mix for the ambient temps, etc...
I suspect an injector leaks on my '97 from time to time...occaisionally, and only in cold weather, it smells slightly of gas in the morning and one cylinder misses for a few seconds after start up...oddly it has never coded for misfire though...
Could be you just got some watery gas making some ice crystals overnight in the line if it's that cold there...has to be pretty damn cold for that though...