This is a case for cheap thermometers that you can find on Aliexpress: [https://www.aliexpress.com/item/Mini-LCD-Digital-Thermometer-Hygrometer-Fridge-Freezer-Tester-Temperature-Humidity-Meter-Detector-Thermograph-Pet-Auto-Car/32861882092.html?spm=a2g0s.9042311.0.0.4e134c4dmxVxYF](https://www.aliexpress.com/item/Mini-LCD-Digital-Thermometer-Hygrometer-Fridge-Freezer-Tester-Temperature-Humidity-Meter-Detector-Thermograph-Pet-Auto-Car/32861882092.html?spm=a2g0s.9042311.0.0.4e134c4dmxVxYF)
The one you can see in the picture was printed with included gcode. I just wanted it fast so the ribs in the back are a bit ugly.

Thermometer should fit in very snugly and if it doesn't you can always sand the hole a bit, since the lip on thermometer hides it.

If anyone is interested I can also provide Fusion360 file.