So, I edited my session to set up alerts on low/high temperatures.
The email I received straight away contains:
Normal Temperature Alert
The temperature of your session 'Device-Initiated Session' has returned to normal.
Low temp alert threshold: 10.5 °F
Current temperature: 18.8 °F
This is totally wrong. The current temperature is actually 18.8 C. It's been intepreted numerically as F. My low-temp threshold was 9F below set-point (because I couldn't configure it in C hint) and so has now been incorrectly set at 10.5F.