@Ostentatio
Probably because it was only about 11% implemented by default
at the time. There is a range of 255 steps to usable elevation
meaning bedrock to our highest normally allowed build height.
There were only 28, levels in xml, so unless a person modded it,
then temperature felt really abrupt as you moved. Once modded, it
felt in synch with the elevation.
There were 23 variables, that adjusted for environmental location,
and personal changes, like DryTempCutoff, CoreTempChangeRateWhenDry,
EnclosureDetectionThreshold which was really generous at .15, etc. These
allowed weathersurvival to feel like a part of the game, but only if the
complete elevation was modded. But very few people modded it, so; most people
remember it the way that you do.
One of he reasons it would have felt different when you returned is because
the new RWG is based on a plane instead of elevation. So your memory is correct if
you didn't mod to allow for elevation back then.