Temporal trends of daily extreme temperature indices in North-Central Mexico

A temporal trend analysis of weather variables is needed for developing mitigation and adaptation strategies to climate change. The objective of this work was to study temporal trends of 17 extreme temperature indices in North-Central Mexico (NCM). We used daily observations of maximum and minimum temperatures from 127 weather stations for 34 years (1980-2013). The extreme temperature indices were calculated with the RClimDex v1.9 package. Analysis of trend indices was carried out with the Mann-Kendall technique and the rate of change with the Theil-Sen estimator. Except for the growing season length, all-temperature indices showed statistically signifi cant positive trends (SSPT) ( p = 0.05) between 1 and 62; except for the cold spell duration indicator, all indices showed statistically significant negative trends (SSNT) between 3 and 62.The SSPT of all indices varied between 0.246 degrees C decade-1 (TMINMEAN) and 48.000 days decade-1 (SU25),while the SSNT varied between -55.238 days decade-1 (SU25) and -0.181 degrees C decade-1 (TMINMEAN). In NCM, the increase in some indices could be causing an increase in crop water requirements and poorly meeting some crop's chilling requirements. In crops, such as grapevine, peach, and apple, an excellent short-term strategy to adapt to the decrease in cold winter and to compensate for the satisfaction of poor chilling hours using biostimulant of sprouting should be considered. New varieties/hybrids of corn and beans for dealing with the increase in warm days (TX90p), summer days (SU25), warm nights (TN90p), and tropical nights must be available; also, these new varieties should have shorter cycle and should be cold resistant.The results of this work constitute a reliable tool for generating answers for measures of adaptation to the onslaught of climate change in NCM.