Solar variability leaves detectable, climate state–dependent imprints on summer hydro-meteorological extremes. We show that centennial-scale solar minima, including the Maunder and Dalton minima, enhanced summer flooding and heavy precipitation from Western to Southeastern Europe under pre-industrial conditions, by combining a chemistry–climate model with palaeoclimate reconstructions and proxy records. We identify the physical mechanism linking reduced solar irradiance, stratospheric ozone changes, and sea-ice persistence to modified meridional temperature and pressure gradients and a southward shift of the European storm track. Model–data convergence supports this mechanism and its intra-seasonal amplification toward late summer. In a high-emissions future climate, the loss of summer sea ice and a weaker, northward-shifted storm track suppress this pathway, diminishing the sensitivity of European summer extremes to identical solar perturbations. Our results highlight the critical role of background climate state for interpreting solar fingerprints in past records and assessing future risks.