Historical documentary sources in the Canary Islands have been used to construct cereal production series for the period 1595–1836. The cereal growth period in this region covers essentially the rainy season, making these crops adequate to characterize the annual precipitation. A proxy for the Islands' rainfall based on the historical series of wheat and barley production has been constructed and assessed by using two independent series of dry and wet years. The spectral analysis of the crop production reveals a strong non stationary behavior. This fact, along with the direct comparison with several reconstructed and instrumental North Atlantic Oscillation series, suggests the potential use of the reconstructed precipitation as a proxy for this climatic oscillation during preinstrumental times.