Contour Matlab figure (saved as .eps file) is more than 150MB

Question

I am reading a netcdf file in matlab, using ncread. Then I try to do a contour plot of my data, time variable is 3000x1, z(1,:) variable is 1x200, and the resulting X1 and Y1 variables are both 200x3000. When i try to save the figure produced in .eps format i get a file sometimes as big as 200MB that when i try to open sometimes crashes. Am i doing something wrong with the contour plot?

[X1,Y1]=meshgrid(time',z(1,:));

figure
contourf(X1,Y1,precip(:,:,1)','ShowText','on');