What is the temperature of freezing of a camera?

I'm going to Alaska and I have a Nikon 5000 and I found a place where it says that wan person took his camera and it freeze.
I can't found where says at what temperature it freeze Please help

Nikon likes to protect itself from liability by advising against using the camera below freezing. It should work, but as the temperature goes much below freezing the battery goes dormant. You can get around this by carrying the camera in a padded case with several handwarmer packs. Think out your photo before deploying it, and keep exposure of the camera to the cold brief. If you use a tripod (which you will need if you want to photograph the aurora), it helps to have a model that uses a quick release plate. Have an extra battery in your pocket to keep it warm. Have clean cotton handkerchiefs to wipe off condensation. Avoid working barehanded in the cold. Use glove liners. Sandwiching a handwarmer pack between two glove linders can allow adequate dexterity and adequate warmth for a few minutes work.
This was taken with a Nikon D50:

For the aurora, set your white balance to the daylight preset. To autofocus you may need to point the camera at something bright and distant to lock in the autofocus, and then switch the lens to manual focus, being careful not to disturb the setting. You might need to turn your headlights onto something to get adequate illumination for the autofocus. If you have a lens with a distance scale you may be able to dial it to infinity. For many lenses these distance scales are not accurate. Experiment in advance at home in milder conditions.

I have used my Nikon D40 slightly below 0°F (-18°C) without problem. I let the camera go down to ambient temperature. You will have reduced battery capacity at low temperatures. The biggest problem with cold weather is bringing the camera indoors which causes condensation on the camera parts. Before going indoors, put the camera in a plastic bag and let it warm up indoors for 45 minutes before removing from the bag.