import seaborn as sns

sns.set_style("whitegrid")
tips = sns.load_dataset("tips")
box_plot = sns.boxplot(x="day",y="total_bill",data=tips)

medians = tips.groupby(['day'])['total_bill'].median()
vertical_offset = tips['total_bill'].median() * 0.05 # offset from median for display

for xtick in box_plot.get_xticks():
    box_plot.text(xtick,medians[xtick] + vertical_offset,medians[xtick], 
            horizontalalignment='center',size='x-small',color='w',weight='semibold')