If your define a @context on your WebThing that references Mozilla’s types, you can use the following @type values for a Property:
https://iot.mozilla.org/schemas/#properties
Two properties for temperature (current and target) have already been mentioned here: (Thread: Web Thing API: Read-only and slow properties)[Web Thing API: Read-only and slow properties]
Would be cool, if we could get those into the schema. I don’t know what is missing for the decision to include them.