One suggestion in other answers is to use ax.set_axis_bgcolor("red")
. This however is deprecated, and doesn't work on MatPlotLib >= v2.0.
There is also the suggestion to use ax.patch.set_facecolor("red")
(works on both MatPlotLib v1.5 & v2.2). While this works fine, an even easier solution for v2.0+ is to use
ax.set_facecolor("red")