Get an IR temp gun. Amazon has many options.
For a gauge I like these. They're cheap but work surprisingly well. I've compared then with my cigar hydrometer and they were very close. The temp gun can check your hotspot and the other will track the air.
https://www.amazon.com/Zoo-Med-Econo...ed+thermometer
Every Accurite probed unit I've bought has failed. I'm done with them.