Hi! If you're referring to the exercise Probability of High Temperatures, the suggested way is df_climate.loc['2010-Aug','Temperature']
This is the standard way of extracting/filtering data from a DataFrame.
You may be confusing this with something like df_climate[df_climate['Temperature']>20]. This works because df_climate['Temperature']>20 returns a boolean Series, which the DataFrame df_climate can use to filter its rows. df[df.loc['2010-08', 'Temperature']] doesn't work because df.loc['2010-08', 'Temperature'] returns a Series with dtype float64, which is not bool.