Is adiabatic heating or altitude the reason for warmer temperatures in the Utah canyonlands in winter? (snowy, days)

[Silent1Unknown15]

Last March when I traveled through Utah I camped out several days around the desert. Near Moab after seeing the temperatures I chose to drive into the canyonlands rather than camp out at the rim or high plateaus because the temperatures were 20 degrees warmer and above freezing in the valleys vs below-zero and snowy on the rim/plateau. I wish I had a Windy screenshot but everything outside the canyons was below-zero in the early morning and 40 degrees and frost-free in the Needles district. I'm curious if the difference in temperature has to do with adiabatic heating as air descends into the canyons, or if the significant elevation difference of 2K' and change in temperature with altitude causes this effect, or maybe both.

[WesterlyWX]

Being an extensive plateau of largely flat topography, there is little to no uplift which in turn makes for a nigh to nonexistent decrease in temperature, even with thousands of metres of altitude.

Uplift, is what causes the drop in temperature. No uplift = no temp drop. Denver at sea level, would thus be little-different to how it is currently at 1700m.