It's Always Sunny in Politics

The extant literature suggests that precipitation—mainly in the form of rainfall—has a significant impact on electoral outcomes. This paper adds to this literature by investigating an understudied dimension of weather—sunshine. Using novel daily weather measurements from satellites, linked to county-level U.S. Presidential electoral returns from 1948-2016, we document how sunshine affects the decision-making of voters. We find that election-day exposure to sunshine increases support for the Democratic party on average. Additionally, we show that, contrary to prior findings that do not control for sunshine, precipitation has no detectable impact on partisan support, but universally depresses turnout. To rationalize our results we propose a mechanism whereby sunshine modulates voter mood which causes a change in voter choice, while precipitation only impacts turnout by increasing the cost of voting. We then build a theoretical model, which features this mechanism, and generates additional tests that we take to our data. Our results suggest that uninformative weather on election day, specifically sunshine, have detectable electoral impacts that teach us about voter choice. Classification- D7, D9, P1