Please advise me best relaible digital professional camera to use in himalaya mountains & desert for personal

I live in dubai. I am planning a trip to himalayas mountains. I need a digital camera to buy which suits both hot summer 50 degree and cold - 10 degree temperatures with complete kit.
I was given to understand that battery loses charge in cold temperature so i need to know the quality one to carry with me. please someone who knows about it give me advise.

How much are you willing to spend? You will need a camera that is enviromentally sealed. The Canon EOS 1Ds Mark II or the Canon 1D Mark II N. If you want a Nikon you can get the Nikon D2Hs or Nikon D2H. All of these are excellent prosumer cameras but you will have to buy expensive glass for the camera to shine. The D2Hs is a 4MP camera if you do not need all of those 16MP from the Canon 1Ds Mark II. For Canon you want to buy their L lenses because every pixel will hold lots of details and you will need excellent glass. If it was up to me I would get the Canon 1D Mark II if I had $4000 + $3000 in lenses.

All digital cameras are built to endure weather conditions.

Only, try and carry a camera that can use standard A4 size batteries, then buy the rechargeable batteries and carry the charger with you. The advantage is that these batteries are easily available in most tourist places.

i hav use my trusty Canon 30D in conditions as cold as -10degree.. no problems at all...though the battery does loses
it charge but tat pretty normal. Maybe u can use a battery grip and bring lots of AAA batteries...

Unless you plan on taking a computer up the himalayas, you will have no way to download your pictures. Use a film camera and save yourself the expense of buying a couple of dozen memory cards. A simple non-electronic camera holds up better in super cold conditions.