It's the Weather, Stupid

We’ve written in the past about how weather can have a surprisingly strong effect on things like civil war and riots. (Short story: rioters don’t like getting rained on and droughts can start a war.)

The political scientist Peter Kurrild-Klitgaard has a new paper on the topic in Public Choice (abstract; PDF) called “It’s the Weather, Stupid! Individual Participation in Collective May Day Demonstrations.” The bolding is mine:

“We investigate the possible explanations for variations in aggregate levels of participation in large-scale political demonstrations. A simple public choice inspired model is applied to data derived from the annual May Day demonstrations of the Danish labor movement and socialist parties taking place in Copenhagen in the period 1980–2011. The most important explanatory variables are variations in the weather conditions and consumer confidence, while political and socio-economic conditions exhibit no robust effects. As such accidental or non-political factors may be much more important for collective political action than usually acknowledged and possibly make changes in aggregate levels of political support seem erratic and unpredictable.”