  The analysis of the night cloud cover is very important for astronomical
observation in real time, considering a typical observation time of about 15
minutes, and to have a statistics of the night cloud cover. In this paper we
use the SQM (Sky Quality Meter) for high resolution temporal analysis of the La
Silla and Asiago (Ekar observatory) sky: 3 and 5 minutes respectively. We
investigate the annual temporal evolution of the natural contributions of the
sky in a site not influenced by artificial light at night (ALAN) and one highly
influenced respectively. We also make a correlation between GOES and AQUA
satellites data and ground-based SQM data to confirm a relationship between the
SQM data and cloud cover. We develop an algorithm that allows the use of the
SQM for night cloud detection and we reach a correlation of 97.2\% at La Silla
and 94.6\% at Asiago with the nighttime cloud cover detected by the GOES and
AQUA satellites. Our algorithm also classifies the photometric (PN) and
spectroscopic nights (SN). We measure 59.1\% PN and 21.7\% SN for a total
percentage of clear nights of 80.8\% at La Silla in 2018. The respective Ekar
observatory values are 31.1\% PN, 24.0\% SN and 55.1\% of total clear nights
time. Application to the SQM network would involve the development of long-term
statistics and big data forecasting models, for site testing and real-time
astronomical observation.
