How do I assign a title to each of the histograms I have posted at the same time?
Using the axes variables you have, which is a numpy.ndarray of size 7

axes[0].set_title('Title for Fig. 1') #change title for first histogram
axes[1].set_title('Title for Fig. 2') #change title for second histogram
axes[2].set_title('Title for Fig. 3') #change title for third histogram