Technical Abstract: The purpose of this chapter is to review the climatic data for the Jornada Basin over the period for which instrumental records exist. Over this time period, up to 83 years in the case of Jornada Experimental Range, we can deduce both the long-term mean characteristics and variability on a range of different spatial and temporal scales. Short-term variability is seen in individual rainstorms, whereas longer-term patterns are controlled spatially by factors such as large-scale circulation patterns and basin and regional orography and temporally by the large-scale fluctuations in atmospheric and oceanic circulation patterns. Variability can have significant impacts on the biogeography of a region or on its geomorphic processes, which may set in motion a series of feedbacks, most importantly those referring to desertification. Understanding the frequency and magnitude of such variability is therefore fundamental in explaining the observed landscape changes in areas such as the Jornada Basin.