GoingForGold:
To make it a bit clearer, I am a Hot Air Balloon pilot, and we do have instruments with huge LCDs (although black and white and without touchscreen, but they are 15x8cm) which work under these conditions. Since it is an device for flight safety I wont open it to look how they're doing it.
I bet they do have heaters. Have you looked into Kapton flexible heaters? Very nice to have around electronics. Some batteries even have heaters to maintain operating temperature.