  Dome A in Antarctica has many characteristics that make it an excellent site
for astronomical observations, from the optical to the terahertz. Quantitative
site testing is still needed to confirm the site's properties. In this paper,
we present a statistical analysis of cloud cover and aurora contamination from
the Kunlun Cloud and Aurora Monitor (KLCAM). KLCAM is an automatic, unattended
all-sky camera aiming for long-term monitoring of the usable observing time and
optical sky background at Dome~A. It was installed at Dome~A in January 2017,
worked through the austral winter, and collected over 47,000 images over 490
days. A semi-quantitative visual data analysis of cloud cover and auroral
contamination was carried out by five individuals. The analysis shows that the
night sky was free of cloud for 83 per cent of the time, which ranks Dome~A
highly in a comparison with other observatory sites. Although aurorae were
detected somewhere on an image for nearly 45 per cent of the time, the
strongest auroral emission lines can be filtered out with customized filters.
