Larry outlined the main problems pretty well, especially the LCD problem--I've had digital watch displays fade out at low temperatures.

The most stressful time in the life of electronic equipment is when power is applied, and a lot of component failures at startup are due to thermal shock. The worst thing would be for your laptop to be cooled to a cold ambient before you apply power. You'd be well advised to have it running indoors for a while before taking it outside, and then keep it running (turn off any sleep feature). Laptops are designed to minimize heat, but what little heat the components give off will help keep it warmer than ambient...by a little bit, anyway.

Good luck!

--Robert