It has been estimated that summer precipitation would have increased by and temperature dropped for Lake Tauca to form. According to a 1985 estimate, increased precipitation of would be needed; the estimate was subsequently revised to . With a temperature decrease, a 20-75% increase in precipitation would be required to form the lake. Research in 2013 indicated that the climate at the Tunupa volcano (in the centre of Lake Tauca) was about colder than present, with rainfall estimated at . An even more recent estimate envisages a temperature decrease of and a mean precipitation 130% higher than today, about ; this precipitation increase was concentrated on the eastern side of the catchment of Lake Tauca while the southernmost watershed was almost as dry as present-day. In a coupled glacier-lake model, temperatures were conditionally estimated at lower than today. In the southern Altiplano, precipitation exceeded during this epoch. In the central Altiplano, precipitation was 1.5 to three times higher than today.