medians = tips.groupby(['day'])['total_bill'].median().values
median_labels = [str(np.round(s, 2)) for s in medians]
pos = list(range(len(medians)))
for tick, label in zip(pos, ax.get_xticklabels()):
    ax.text(pos[tick], medians[tick] + 0.5, median_labels[tick],
        horizontalalignment='center', size='x-small', color='w', weight=
        'semibold')
Labeling boxplot in seaborn with median value