In comparison with many remote parts of the Earth, the watershed Sibinacocha Lake is poorly studied region and the various types of life that habit this region are highly dependent on the waters of this glaciated basin. The present study evaluates the snow cover in this basin associated with changes in air temperatures and precipitation during the period 1984 to 2019. It used the ERA5 high-resolution reanalysis data from the European Centre for Medium-Range Weather Forecasts (ECMWF) and 35 images from the Landsat satellite. The results showed a statistically significant positive trend in maximum air temperatures whose signal is in agreement with previous studies. Seasonal analysis of maximum temperatures showed positive trends in all seasons, indicating that the highest trends occur during winter and the lowest trends during the southern fall. In addition, there was a 26% decrease in snow cover in general in the basin, and it was evidenced that the greater decreases (53%, approximately) occurred in regions below the altitude of 5300 m. In fact, from this contribution of the study comes the need to carry out more research in this region, especially to support decisions covering agriculture, water resources management and biodiversity studies.