In your manual, there should be a line in the specs which states what the operating limits are. The upper temp and lower temp shown are most likely minimums and if you choose to operate your camera in temperatures above or below given numbers, you run the risk of a malfunction. I would say that leaving you camera in the car all day in sub-zero temps is probably not the best idea.
Thanks. Note that I didn't say "sub-zero".
As mentioned the manual states the range of temperatures under which normal operation can be expected - outside that all bets are off. More important than whether or not you leave you camera equipment in a sub-zero car is how you bring it back up to room temperature since condensation can wreak havoc in both bodies and lenses. Even a warm, dry house has more humidity than the outside air, so you want to bring the temp up slowly, and if possible in a sealed environment like a large ziplok that gets put on outside in the cold.
Usually in a nice warm, dehumidified safe. Also, I ALWAYS safe those little desiccant packets that come in pill bottles and bubble wrapped packages and such. Those go in the dehumidified safe, too, to keep them fresh. Those are perfect for inside the ziplok bag as you mentioned. I intend to take a short walk today with the camera. It's about 28°F outside with partly sunny sky and light wind. It's fairly dry. I'll let you know how it goes.
Side note: I always wondered why some places still use Celsius, when Fahrenheit is so much more accurate, temperature wise.
Most countries in the world use Celsius. Those that use Farenheit include: USA, Bahamas, Belize, Cayman Islands, Palau, American Samoa and the US Virgin Islands. Puerto Rico and Guam use either Celsius or a mix of both.
I personally would not leave my camera in the car in freezing temperatures if I did not have to,
could you not take it with you, or leave it at home.