Do different zones have a resting temperature?

There are no special properties of biomes other than what starts in them. There's no hidden propery of the cold biome that magically removes heat.

Your starting area might eventually get back (down, I assume) to 23C if the average temperature of the asteroid is cool enough, but it won't do it via any implied 3rd dimension heat transfer.

https://oxygennotincluded.gamepedia.com/Biome