Resumen
Annual average of daily precipitation was used to group climatological stations into clusters using the k-means procedure and principal component analysis with varimax rotation. After a careful selection of the stations deployed in Mexico since 1950, we selected 349 characterized by having 35 to 40 complete years of observations. The clustering of stations was performed three times: firstly according to the amount of precipitation; secondly according to their anomalies from the mean, resulting in their standard deviations grouping; and thirdly using the standardized anomalies, which resulted in a clustering according to the features of the trend and the structural changes of the series over the observing period. We identified two clusters that occupy northwestern and north-central Mexico; another at the center of the territory, between Sierra Madre Oriental and Sierra Madre Occidental; the following over the Sierra Madre Oriental; and a last one in the southeast of the territory, the southern coast of the Pacific Ocean and the Yucatán Peninsula, that overlaps with Sierra Madre Oriental group. Some stations of Yucatán Peninsula show similar characteristics to the northwestern cluster. The groupings were compared with the results of previous studies. The comparison indicates that regions are invariant in time and space and independent of the method of agregation and the stations sampled.