Battery draining in cold weather is really fast. My camera top LCD normaly shows 999 remaining shots with full battery and almost empty CF. But today, when i try to take several pictures outside and temperature was around -12 C (around 10 F), i noticed that LCD shows only ~270 remaining shots. And camera was only 2 - 5 minutes in that cold weather. So..you should have to have at least 2 batteries, if you want to spend half-day taking pictures in such a cold weather.