@dmcinnes - Looks good.
There was a fork(?) of the original Magic Mirror (version 1) code which replaced the standard weather module using data from Dark Sky’s forecast.io API - see https://github.com/jangellx/MagicMirror
This included a graph of temperature/rain, a forecast for the week ahead and a summary of current weather - see https://github.com/jangellx/MagicMirror#important-installation-note
Code seems to be contained in https://github.com/dmcinnes/MMM-forecast-io/blob/master/MMM-forecast-io.js
Any chance your MM² module could be extended to include this too?