MAX-DOAS instruments measure scattered light in both the ultraviolet and visible regions of the solar spectrum. Such measurements allow for the characterization of the concentration and distribution of trace gases and aerosol extinction in the atmosphere. Wagner et al., 2016 develop a method for calibration of color index using a ratio of intensities at two pairs of wavelengths (330 nm and 390 nm, 320 nm and 440 nm) to apply to a standardised cloud classification algorithm for MAX-DOAS measurements. The color index is dependent on a calibration factor unique to each instrument, and we apply the methodology in Wagner et al., 2016 to the CU MAX-DOAS at the Salt Lake City (SLC) Utah Department of Air Quality Inland Port Site, where the instrument was deployed in February 2023 and has been taking near continuous measurements since. Classification of cloud cover is crucial to determining reference spectra for MAX-DOAS measurement retrievals which depend on clear-sky conditions, and can facilitate the assessment of MAX-DOAS performance in cloudy conditions. Cloud classification can also facilitate the identification of persistent cold air pool (PCAP) periods, which are significant drivers of poor air quality in the greater SLC area. In this work, we calculate the calibration factor for the SLC MAX-DOAS to determine clear-sky and cloudy periods. We create a time series of cloud classification throughout the study period to identify clear periods suitable for reference spectra, in order to generate a long-term time series at SLC of IO radicals, BrO radicals and other trace gases such as NO2.