The state of the atmosphere regarding the air density profile, the vertical distribution of aerosols, and the location of clouds is closely monitored at the Pierre Auger Observatory because the troposphere serves as a giant calorimeter for the air fluorescence technique. We present an overview of the atmospheric monitoring instruments at our disposal, with a focus on their capabilities for real-time measurements and their importance to extensive air shower reconstruction. We detail the improvement of our database of aerosol attenuation measurements that has been extended by two more years to the end of 2017 and fully recalculated with new software that brings a range of enhancements. We also address the importance of using hourly measurements of aerosol distributions for analyses rather than static models of average atmospheric conditions.