It was a 12.5 mile (RT) hike from El Chaltén (Argentina). Five of us started our hike at 4:00 AM in order to make a sunrise shoot. About halfway into the hike we descended into a lower valley. . . and the temps descended with us - I am guessing it was about 15 degrees fahrenheit!
When we stopped to eat breakfast at a camp area under the trees (a “warmer” area) we could not stay warm. Just before sunrise we hiked the rest of the way to Laguna Torre. Once we topped the crest and in the early predawn light saw the frozen lagoon and the Cerro Torre mountains I forgot all about being cold.