Hi again,

I would say you have a rich mixture problem or you are not holding your mouth in the proper shape when it doesn't start.
I suggest you look in the rear view mirror when it starts up in sub temps just to see if you are only gritting your teeth or being tight lipped about the whole affair when it happens. The cold air can cause the mouth not to droop or distort as much. (:-)(|)

Kidding aside, it's must be not be flooding the plugs with "vaporized fuel" AND since the air is colder, the air itself is more dense so the mixture "In Turn" is leaner when it's colder than it is when it's warmer and causing vapor action to occur.
The only variable looks to be the air to the fuel ratio, that is assuming and I hate that by the way, the Engines Coolant Temperature sensor is working correctly. We have no idea about that guy adding or taking away fuel or just pulsing the same amount in both cases.
It can be checked at a ECU pin for either Ohms or Voltage in some write ups.

Air temperature would make more sense in the overall picture with only the air temperature changing but it's another guess!
The air temperature should affect the battery performance some, but it starts up now. There is enough current and voltage left to provide spark in both starting conditions.

If we center in on the CPS it can be effected by temperature and cause the problems as Art has suggested. It is a known fact that the CPS can exhibit random and somewhat peculiar starting or running performances.
If the signals it produces, do not fall exactly in line with what the ECU expects to see, it fouls up the programming inside and it starts "guessing," as Art says we do, except it takes action right or wrong.
Wait, we do that too! Bad information seems to be a norm nowadays.

So my guess is a mixture change going on.
If you rule out the electronics involvement, you have to look at the intake manifold gasket going with temperature change. A snorkel tube behind the AMM has cracks with thermal change and there is always a throttle body adjustments. The switch working to tell the ECU its is to be in idle and start mode is required. Pumping the throttle is a no-no and if it starts it becomes a big clue fo me as to something is not correct.

(:-) of course I'm guessing!
Phil