Phenological data observed on the ground, together with satellite data, are crucial tools to identify the vegetation growing season. Using a geostatistical approach, this study aimed to determine the seasonal dynamics of flaggrass [Bouteloua curtipendula (Michx.) Torr.] in Chihuahua and its relationship with climate variability. The metrics of the beginning (SOS) and end (EOS) of the growing season of this species in the state of Chihuahua were calculated. In addition, the effect of air temperature and precipitation on the dynamics of SOS and EOS during the periods 2000-2010 and 2011-2019 was evaluated. The treatments considered the three ecological regions (desert, central valleys and sierra) and the years of record. The state was studied through three ecological zones: desert (D), central valleys (CV) and sierra (S) for comparison. SOS and EOS of flaggrass in each zone were defined annually from Landsat data during the period 2000-2019, based on the dynamics of the Normalized Difference Vegetation Index (NDVI). SOS ranged from May to June (mean Julian day [doy]=174), while EOS ranged from October to November (mean Julian day [doy]=283). A delay in SOS was observed in zone D; the delay in flaggrass growth in the spring season may be due to a relative scarcity of water, although the higher temperature in spring facilitates the fulfillment of the thermal requirements for the growth of the species. These findings suggest that climate variability has a significant impact on the seasonal dynamics of flaggrass, which may influence management strategies for these ecosystems.