i don't see that option on the gauge. In case you are doing a horizontal gauge, you can easliy convert that to a bar chart.
When you do this enter a synthetic dimension for the bar (the gauge requires no dimension). Something like this:
The measure would stay the same.
Then open up appearance and you'll have the ability to switch it to a vertical or horizontal bar AND color by Expression. You can use a lot of color funcitons in the expression. Here is something basic:
if(Month='Jan',Red(), if( Month='Feb', Yellow() , if(Month='Mar',Red() ) ) )
You can actually store the colors in an external source or calculate them at load (by month) and render the color dynamically based on the selection.
Let me know if you need help setting up the bar chart or the dynamic colors