<p>Amid China’s persistent challenges of high carbon emissions and structural pollution, the increasing frequency of extreme weather events has further complicated the achievement of its dual carbon goals. Analyzing the impact mechanisms of extreme weather on the synergy between carbon reduction and pollution control holds significant practical importance for improving the climate governance system. Using panel data from 31 provincial-level regions from 2011 to 2022, this study applies the Mann–Kendall trend test to identify spatio-temporal evolution characteristics of synergistic effects, while employing HP filter and random forest models to evaluate the impact of extreme weather and its driving mechanisms. The findings reveal that (1) China’s carbon reduction and pollution control synergy showed a slowly improving but fluctuating trend during the study period, with limited overall progress; (2) significant regional disparities in synergy levels were observed, and these differences continued to widen as extreme weather impacts intensified; (3) extreme weather significantly inhibited synergistic effects by disrupting energy system stability and pollution control efficiency, creating a dynamic interplay between policy dividends and climate risks; and (4) dominant driving factors varied substantially across different extreme weather scenarios, where energy transition and technological capability were particularly critical for addressing extreme heat; government intervention played a prominent role in managing extreme precipitation; industrial upgrading and human resources were more important for coping with extreme cold, while opening-up demonstrated unique value in mitigating extreme drought impacts. These findings provide a scientific basis for developing differentiated and targeted climate adaptation policies.</p>