The colour scale that is used for the plots. The default is optimised for anomaly plots, with a grey band in the middle that is two times larger than the colour bands. Yellow-orange-red to the positive values, green-blue to negative ones. For precipitation and ice anomalies a reversed colour scale is more intuitive.
Note that a distinction is made between values around zero, which are grey, and undefined value, which are white.
For non-anomaly values (mean, standard deviation, ...) there are colour scales available that do not have grey in the middle.