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A new geochemical record from the paaleolake Santiaguillo documents the hydrological variability of sub-tropical northern Mexico over the last approximate to 14cal.ka. Summer-season runoff, lake water salinity and deposition of sediments by aeolian activity were reconstructed from concentrations of K, Ca and Zr/K in bulk sediments. More-than-average runoff during c. 12.3-9.3cal.ka BP represented an interval of enhanced summer precipitation. Arid intervals of c. 14-12.3cal.ka BP and c. 6-4.3cal.ka BP were characterized by average and more-than-average aeolian activity. Comparison with proxy records of summer as well as winter precipitation from tropical and sub-tropical North America and sea surface temperatures from the Atlantic and Pacific provides insight into the source of moisture and possible forcing. The wet Pleistocene-Holocene transition and early Holocene was contemporary with warmer conditions in the Gulf of California. We suggest that the Atlantic had minimal influence on the summer precipitation of the western part of sub-tropical northern Mexico and that the source of moisture was dominantly Pacific.