Having lived in New Mexico now for the last 4 years (and El Paso before that) I noticed I've acclimated. Now when it gets below 68 degrees I find I need a thick shirt especially if it's overcast and windy. A friend of mine is an airplane mechanic in Alaska, he claims when it gets up to 60 degrees he's sweating.Very true. I word at a heavy diesel shop In Steamboat Springs, CO. back in the 80' and early 90's. I had insulated Carhartt Bibs and Jacket. I was at the mine changing a front seal, on an Allison trans. in a 200 ton haul truck, temp close to -35. About 2 hours after the sun was out the jacket came off, and very comfortable. I set the seal up in the bore of the front cover and hit it with my hammer, damned thing just exploded and fell apart. I had it laying outside while I disassembled the drive line, etc. Had to dig up another seal.