Note to users:
Be careful when copying the example files here - the encoding of the unit of measurement in the code above:
unit_of_measurement: "°F" and unit_of_measurement: "°C"
May not copy and paste in proper UTF-8 format and will cause HA to fail to start without producing an error log depending on your editor. This messed me up for a sleepless night until I got some help figuring out what the problem was. You can read more about it here:
Not sure if this is dependent on your editor, but I am using the same editor I have been using since I started using HA and never ran into this issue before. I raised a bug on github for it.