There are some morons commenting here
First of all, people regularly use their phones at -20'C or beyond - where I live (in the Nordic countries), -20'C is normal in midwinter time and I've seen it down to -35'C quite happily. A couple of winters back I believe it got down to -50'C in Moscow, although I don't believe that greater than -40'C is usual. That said, my Nokia 5200 worked in -15 to -20 just fine, and I haven't had any problems so far with my N70.
@ extreme sports
Anthony, you're a plonker.
"if you were busy scuba diving, couple hundred metres under water, incoming call - no problem, you've got this phone. Does it give you the ability to speak underwater? Didn't think so. You're trailblazing down a mountain on your mountain bike (naturally), your phone rings.. and grants you the ability to ride down a mountain one handed? Comes with a parachute for when you fall off the mountain? Turns into a spare wheel and a six pack?"
You're right, you're not always going to answer if it rings midway through something. But I do whitewater kayking and I have friends who do other extreme sports, and sometimes you just like to have a phone with you (in case of emergency etc). If I capsize in a rapids, sure I keep my phone in a tough watertight bag and on my person, but what if a) I hit a rock phone-first (shock damage), or b) the rock catches on the bag and rips a hole (water damage). This type of rugged phone sounds just perfect for those situations.
If you think "don't take it with you" is the answer when doing a dangerous sport away from civilisation and the nearest hospital, then you're a moron and more than that, showing a callous disregard for the safety of yourself and your companions. In these situations, it's not just a leisure toy; it's a potential rescue tool. More than once a kayaker who has been swept further downstream has phoned upstream to let us know he's okay, so we didn't have to panic. Not to mention the fact that after my sport is over I might want to phone the driver to pick us up from wherever we ended up (eg, unexpected change of plans), or let my wife know I survived. This is just common sense, I'm amazed you didn't spot it.