The terahertz (THz) band has drawn considerable attention for potential telecommunication applications. This band of the electromagnetic spectrum provides greater bandwidth and thus allows for transmission of data at higher speeds. Yet, a limitation for the real-world use of this part of the spectrum is the strong absorption of atmospheric water vapor. The ITU-R 676-13 recommendation from the International Telecommunication Union provides an empirical model that remains the standard reference for the estimation of the attenuation of the atmosphere. This model is widely accepted and has been confirmed by a number of experimental studies of the attenuation of THz signals for a variety of atmospheric conditions, including some data that we present here.