The DESI Sky Continuum Monitor System tracks the night sky brightness as part of a system that dynamically adjusts the spectroscopic exposure time to produce more uniform data quality and to maximize observing efficiency. The DESI dynamic exposure time calculator (ETC) combines sky brightness measurements from the Sky Monitor with data from the guider system to calculate the exposure time to achieve uniform signal-to-noise ratio (SNR) in the spectra under various observing conditions. The DESI focal plane system includes 17 sky fiber that are split into two groups that are fed into two identical Sky Monitor units to provide redundancy. Each Sky Monitor unit uses an SBIG STXL-6303e CCD camera with an eight-position filter wheel. Both units have been in operation at  the Mayall 4-m Telescope at the Kitt Peak National Observatory supporting on-going DESI science survey operations since 2020.