Historical trends reveal significant increase in hot-dry extremes in Mexico's Bajío region.

This study provides a first-of-its-kind comprehensive analysis of temperature and precipitation extreme trends in the Bajío region of Mexico over the past four decades, utilizing high spatial resolution reanalysis data. Our findings reveal a compelling and consistent warming trend, characterized by a significant increase in warm days, warm nights, warm spell duration, and summer days, alongside a notable decrease in cold extremes. This widespread warming has profound implications for agricultural sustainability, primarily through increased heat stress and evapotranspiration. In contrast, precipitation trends exhibit a complex and spatially variable picture, with a predominant decrease in intense 5-day precipitation, consecutive wet days, and total wet-day precipitation, while 1-day extremes and the frequency of heavy rainfall days show more mixed or stable patterns. The exploration of a large set of global drivers provides a broader context for understanding these regional changes. Despite some limitations, such as potentially unbalanced data in composite analysis and the masking of certain extremes by reanalysis data, this research is crucial for understanding regional climate impacts and informing future studies. The observed shifts necessitate targeted adaptation strategies for water resource management and agricultural planning to ensure the long-term sustainability of the Bajío region.