Day-to-day variations in temperature and precipitation are key metrics of rapid weather variability, with profound implications for human health, agriculture, and ecosystem stability. This project aims to investigate historical and future changes in such abrupt changes, as well as the physical mechanisms driving these variations. To diagnose temperature variability, we employ trajectory-based analysis to identify the underlying physical processes, such as advection and adiabatic and diabatic heating/cooling. For sudden precipitation variability, we will apply a moisture-budget diagnostic to quantify the relative contributions of thermodynamics and dynamics. The study integrates observational and reanalysis datasets with ensemble climate model simulations, focusing on variability at seasonal timescales.