Problem with colorbar in subplot

I have made the following code for representing physical measurements in the region of Angola for the twelve months of the year.

All subplots have the same colorbar for easy distinction between months. I want it to have only one big colorbar instead of twelve small ones.

mediamensual=nanmean(datos,3); %this means monthly mean
auxiliar2=max(mediamensual);
m=max(auxiliar2);
mn=0;

f=linspace(0,1,100);

for j=1:12
     subplot(3,4,j)
     ax = worldmap('angola');
     load coastlines
     setm(ax, 'Origin', [0 20 0])
     plotm(coastlat,coastlon);
     hold on

      for a=1:190
      c=(mediamensual(:,j)-mn)/(m-mn);
      color2=[c c c];
          lat=coord(a,1);
          lon=coord(a,2);
          %geoshow('landareas.shp', 'FaceColor', [0.5 1.0 0.5]);
          geoshow(ax, lat, lon, 'DisplayType', 'point', 'MarkerEdgeColor', color2(a,:),'Marker', '.', 'MarkerSize', 10)
      end
         colormap(f'*ones(1,3))
         caxis([mn m])
         colorbar
  end

Any idea is appreciated. Thanks for reading