Red / blue on graph to reflect high / low thresholds

[adamdewey]

Is your feature request related to a problem? Please describe.
Currently the red / blue colouring on the graph is fairly arbitrary and is not particularly useful for the user.

It would be much more useful if the red reflected the upper threshold (usually 8 C) and the dark blue reflected the lower threshold (usually 2 C)

White would be a good colour for temperatures that are within normal range.

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