Aguascalientes is a semiarid, drought-prone region in central Mexico, where extreme drought effects damage human health and the economy. Aguascalientes recently suffered from extreme drought conditions in 2022 and 2023, while central Mexico has been suffering from drought conditions since 2019. The assessment of drought threat requires determination of intensity, duration, extension, and periodicity. Here, the periodicity of Aguascalientes annual precipitation, recorded in Aguascalientes at 12 rain gauge stations with continuous recording periods between 1928 and 2024, is studied using spectral analysis, a method commonly employed to study rainfall. The spectral analysis indicates that the annual rainfall exhibits lapses with characteristic 3-, 5-, 8-, 13-, and 21-year periodicities. A cross-correlation and cross-wavelet between rainfall and climate indexes is performed to identify the attribution of the observed periodicities. Thereafter, the 3-to 8-year band is related to humid years associated with El Ni & ntilde;o, the 13-year band is related to drought associated with solar activity, and the 21-year band is associated with the Pacific Oscillation. As a general result, it is found that a high spectral density is related to precipitation variability, so the current presence of the 3-and 13-year periodicities suggests that the actual high variability epoch since 1989 will continue.