Rainfall, population density and voter turnout

We create a dataset linking rainfall amounts to constituency-level election data for Irish general elections over the period 1989–2016. Rainfall is shown to significantly reduce voter turnout. The marginal effect of rainfall on turnout is greater in densely populated constituencies, where a rainy day decreases turnout by as much as three percentage points (or five percent). Using a theoretical framework based on a rational voting model, we propose two possible explanations for this effect. Firstly, if rural voters have higher civic duty than urban voters, they may be immune to rain on election day. Secondly, mode of transport may play a role. Urban voters are more likely to travel on foot or bicycle, whereas rural voters typically travel by car. Therefore, the cost to voting associated with rainfall may be higher in urban areas. Constituency-level data on mode of transport from 1997 to 2016 provides some empirical support for this hypothesis.