OK, we all know how we have to be cognizant of the cooling effect that going higher into the mountains can have. How when we get our weather history based on towns near to the mountains where we are going to hike, we might need to lower the temp estimates quite a bit to adjust for the several thousand feet of elevation we might gain while hiking near those towns with their long term weather records available to us.
But sometimes it is enough to just be surrounded by steep mountains, rather than up on top of a mountain. IOW, the old temperature inversion, when the air is very calm, and the frigid air on a mountain top, being heavier than warmer air, sinks down into the bottoms. Look at this morning in Wyoming: At Big Sandy Trailhead, 9080 feet, it is about +1F at 0700.
Over the other side of the Continental Divide, at Hobb's Park at 10,100 ft, it is a balmy 29F!
But at the nearby New Fork River, west of Big Sandy at 6800 feet, it is minus 13F!
At the little town of Pinedale 6800 ft station, west of Big Sandy, it is minus 4
On the eastern side of the range, not far from Hobb's Park at 10,100- but down at Bull Lake way down at 5600 feet, it is +5F!
This is not a whole lot of miles between any of these weather stations. But on the west side of the mountains there is a range of +1 at 9080 ft to minus 13 at 6800.
On the east side there is a range of 29F at 10,100 to +5 at 5600 ft! And the colder temps are way lower down. 24* colder nearby at 5000 ft lower elevation!