The 2008/2009 graph shows the night outside minimum temperature in red and the daily amount of gas used in kWh in blue.

Notes 2008/09:

I started monitoring my gas usage in September after I saw the massive gas bills in the previous winter. I had NO idea how gas usage changed during the seasons. I especially did not know how gas usage was related to outside temperatures. After four years on monitoring, I have now answered all the questions I had!