I'm biased living in a °C country, but water seems like a better choice than anything else, since water is a common element that we can easily observe its phase changes and those phase changes effect how we have to interact with it on a daily basis.

Although if I was to improve it I think I'd base it on the temperature range that salmonella can grow, as that seems like it might be useful to be able to remember more easily 😂 🧑‍🍳