Just for fun:
"...
We picked up the 15 most-sold mobile phones in Finland and three others for comparison, and took them into the Technical Research Centre of Finland and their "Weather Room", a specialized research lab where the temperature can be adjusted to a fraction of a degree.
...
Failing First: iPhone 4S

At 0 degrees Celsius / 32degrees F, it was business as usual. At -5degrees C/23degrees F, iPhone 4S and Nokia N9 started showing symptoms: the iPhone reported a sim card error and the N9 claimed its battery was nearly empty.
...
Out of the 18 phones we tested, only two feature phones could survive until these temperatures: a very cheap Nokia C1-01 and a five-year-old Nokia E65, which was one of the devices chosen for comparison. In the end, the Finnish engineers did design the best mobile phones for sub-zero environments. They may not be equipped with high-end touch-screens, but they work! And it's probably not a surprise: the coldest temperature in Finland peaks at -40 degrees almost every winter.
..."
http://www.macworld.co.uk/ipad-iphon...pe=allchandate

Maybe it is time to test my N900. ;-)