Climatic variation in the high mountains of central Mexico: Temperature and precipitation indices at Nevado de Toluca volcano

ABSTRACT The Nevado de Toluca weather station (4283 masl, 19 ºN) has recorded meteorological data for over half a century, and this combination of elevation and duration provides a rare opportunity to study climate trends in a tropical high-mountain environment. The climatic variability during the period 1965-2015 at the Nevado de Toluca volcano was analyzed. Nine standard climate indices for temperature and seven for precipitation were calculated from daily data from its weather station. The results, with a high level of statistical significance, show an increase in the number of days with night frost and cold periods; likewise, results indicate an increase in the diurnal thermal oscillation. Total accumulated precipitation shows an increasing tendency over time, although the periods with precipitation are increasingly isolated. This suggests that seasonal snow on the summit of the volcano will be increasingly isolated but, at the same time, the snowpack will persist longer. This work is expected to serve as a reference for other high-mountain tropical environmental studies, where air temperature and precipitation are crucial issues.