The Apple spec sheet for the iPhone says:
Quote:
Operating ambient temperature: 32° to 95° F (0° to 35° C)
Nonoperating temperature: -4° to 113° F (-20° to 45° C)
Relative humidity: 5% to 95% noncondensing
Operating altitude: tested up to 10,000 feet (3000 m)
In spite of that, I have not had many issues using mine in Alaska. I just make sure to carry it in my shirt pocket inside my jacket. Taking it out for a few minutes to make a call doesn't seem to be a problem.

The only time I had a problem was once when I absent mindedly put it in an outside pocket and went out cross country skiing at about 5 deg F (-15 C). It didn't like that at all, and when I tried to make a call it died immediantly. Once it warmed up again it seemed fine, however.

Although I love my iPhone, and often have it with me when out hiking or skiing, I don't really look at it as a field item. I put it in a baggie to keep it dry, and keep it in an inner pocket so it stays warm. Unless I'm expecting a call, I turn it off to conserve battery. I don't consider an iPhone as a primary GPS, but only a back up.
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"Toto, I've a feeling we're not in Kansas any more."
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