The rain in Spain: Turnout and partisan voting in Spanish elections

This paper uses detailed data on election day rainfall from more than 3000 weather stations as an instrument to estimate the causal effect of turnout on electoral results in Spanish General Elections. The first stage results show that rainfall on election day decreases turnout. Second stage results show that conservatives are greatly hurt by higher turnout. Surprisingly, I find that the main leftwing party is not the beneficiary of higher turnout, but rather other smaller parties. In both stages, I control for local economic conditions and find that higher unemployment increases turnout, and that increases in unemployment benefit the conservative party at the expense of leftwing parties. In combination, the results point to turnout having two components, a more volatile one, which is affected by weather, and a more structural one, which depends on economic conditions such as unemployment.