I would do something like this:
edges = 0:15:360;
N_all(1,:) = histcounts(M1,edges);% Put one histogram per row into N_all
N_all(2,:) = histcounts(M2,edges);
N_all(3,:) = histcounts(M3,edges);
N_all(4,:) = histcounts(M4,edges);
N_all(5,:) = N_all(4,:); % Replicate the last row
R = 1:5; % some arbitrary radial coordinates
theta = edges*pi/180; % angles in radians
try
polarPcolor(theta*180/pi,R,N_all),shading flat
catch
disp('You can find the polarPcolor function on the file exchange')
[theta,R] = meshgrid(theta,R);
pcolor(R.*cos(theta),R.*sin(theta),N_all),shading flat
end
HTH