I wonder if it needs an update because I've just asked one for both temperature and humidity and it was able to tell me.
Also see the comparison table at the bottom of this page: https://www.apple.com/uk/homepod-2nd-generation/
Also see the comparison table at the bottom of this page: https://www.apple.com/uk/homepod-2nd-generation/
Maybe the update also requires iOS 16 on a connected device, I’m still on 15.