Two hundred years ago a very cold and wet summer devastated agriculture in Europe and North America, causing widespread food shortages, unrest and suffering – the "year without a summer". This is usually blamed on the eruption of Mount Tambora, in Indonesia, the previous April, but making a link between these two events has proven difficult, as the major impacts were at smaller space and time-scales than we can reconstruct with tree-ring observations and climate model simulations. Here we show that the very limited network of station barometer observations for the period is nevertheless enough to enable a dynamical atmospheric reanalysis to reconstruct the daily weather of summer 1816, over much of Europe. Adding stratospheric aerosol from the Tambora eruption to the reanalysis improves its reconstruction, explicitly linking the volcano to the weather impacts.