If there is any way to create yourself an area/room that can be warmed up to at least 50 degrees you'd be better off. Use some tarps to make a tent that you can warm with a small space heater. If you can't keep your paint and model in the warmth of the house to the last possible moment. The other factor of the process is the compressor itself. Being in a cold damp room it will be pumping out cold damp air. This can be an issue. Here's where a CO2 setup excels.

What is the reason you can't spray indoors? Odor? SWMBO?

Get a candle melter or coffee cup warmer. Either should help, plug it in out where your painting and use it to warm the paint.   The paint should be a better spraying temp.  I paid less then 10 for mine.