Storms and Ballots: The Effect of Extreme Weather on Turnout and Vote Choice

We examine the causal effect of a sequence of extreme weather events on voter turnout and vote choice by leveraging a natural experiment during the 2026 Portuguese presidential election. The storms struck between the two rounds of the election: a subset of municipalities was severely affected, while others were largely spared. We exploit this exogenous shock by comparing changes in electoral outcomes between treated and untreated municipalities across the two rounds. This pre-analysis plan outlines the hypotheses, materials, and proposed analyses.