All eyes will be on Iowa this Monday as residents place their votes in the Iowa Caucus, the first stage in the nomination process for the US presidential election. Several days ago, it appeared that the elements were ready to throw a wrench into an already complicated process as a blizzard threatened the state. Now it looks like the storm will move in on Tuesday after all votes have been cast, but how much might the weather have really affected voting results?
Many factors play a role in voter turnout and isolating the effects of weather is not easy. The studies that have addressed that question have generally shown that inclement weather does have an impact on voter turnout. Voters who are consistent participants in the process, those who are virtually certain to vote in every election, are generally undeterred by weather, but those who say they are only “likely” voters might be discouraged from making the effort by bad weather. One study that examined presidential elections from 1948 to 2000 found that for every inch of rainfall, turnout decreased by just under 1%, while one inch of snow accumulation decreased turnout by around 0.5%. While these might seem like negligible numbers, in a tight race it might make the difference. Extreme cold has also been shown to exert a negative influence on participation rates, especially among Millennials who are generally less likely to vote than their older counterparts. Turnout for the caucus vote is typically less than that for presidential elections anyway, around 20% on average, and that reduced turnout might enhance a disparity in likelihood to vote between “likely” and “certain” voters.
2016 presidential hopefuls such as Bernie Sanders and Donald Trump whose support depends on voters identifying in the “likely to vote” category (as opposed to “certain” voters) are more likely to have their prospects for victory adversely impacted by inclement weather. The latest polling out of Iowa indicates that Sanders holds a slim lead among “likely” voters, while his opponent Hillary Clinton has a slight lead among “certain” voters, so adverse weather (rain, snow, extreme temperatures) might prove significant. Sanders depends on younger votes from the cities and universities, so even variations in weather conditions on a county-by-county scale might make a difference. Trump’s lead over his Republican opponents seems a bit more secure according to the polls, but a major winter storm on the day of the caucus might have been consequential.
Fortunately for Bernie Sanders and Donald Trump, the dangerous blizzard conditions that will force many Iowans to remain at home look to hold off until Tuesday. Monday morning temperatures will start ranging from the lower 20s north to near 30 degrees south, warming to the upper 30s to lower 40s by the afternoon, cool but actually just above normal for this time of year. Clouds will be on the increase later in the day, but the first snowflakes likely won’t start flying in western Iowa until late Monday night with the height of the storm around midday in the more populated central part of the state, including Des Moines. By then the Iowa caucus results will be known and the political focus will have shifted to New Hampshire, the site of the next primary on February 9th.