Early voting means weather will get in the way of fewer people headed to the polls, and much of the nation is expected to get tranquil weather on Election Day.
In recent elections, researchers have found weather affects turnout but haven’t agreed on exactly how.
In 2007, a study concluded that foul weather — mainly rain and snow — decreased voter turnout and benefited Republicans. For every inch of rain, voter turnout declined by just under 1 percent. And their results showed the bad weather dissuaded Democrats the most.
“[A dry election] would have led … Al Gore to win Florida in 2000,” the study, led by Brad Gomez, a political-science professor at Florida State University, said.
Even so, Fujiwara told the Capital Weather Gang the effect of rainfall on voter turnout “is relatively small.”
“For rain to lower turnout by 0.5 percentage points, we need more than a third of an inch of rain to fall on Election Day — this occurs very rarely in November,” he said.
“We actually find that the effect of rain on turnout has been getting weaker in recent years, and it might even be zero now,” he added. “There are many potential reasons for this, early voting and mail voting being the most likely candidates.”
Forty states plus the District of Columbia have adopted early voting laws, and many voters are taking advantage in 2016. According to the United States Election Project, more than 31 million votes have already been cast.
“Obviously, these laws are likely to mitigate the overall effect of bad weather on voter turnout in an election,” Gomez told the Capital Weather Gang.
Still, Gomez said that voters who wait to cast ballots until Election Day may be among those less motivated to vote, in which case the influence of weather could be more profound.
“It is possible that the portion of the electorate that turns out on Election Day, specifically, is disproportionately composed of peripheral voters, weak partisans who do not vote regularly — this latter group is likely to be most sensitive to the added cost (burden) to voting caused by bad weather,” Gomez said.
More than a century ago, rain on Election Day was thought to help Republicans more than Democrats because Democrats were thought to be a slightly older group that was less likely to venture outside and travel in bad weather.
Decades later, the theory flipped, and Democrats were thought to benefit from rain on Election Day because more Democrats lived in cities with better transportation systems and shorter trips to the polls, while Republicans often lived in rural areas which were more adversely affected by bad weather.
Now that the weather impact on partisans seems to be waning, people are more focused on what sways the critical undecided vote. As of a week ago, FiveThirtyEight said about 15 percent of voters were still undecided.
For those undecideds who make it to the polls, the weather could affect their mood and voting decision, according to a 2013 study by Anna Bassi, a professor of politics at the University of North Carolina at Chapel Hill. A voter who is undecided between two candidates might lean toward a “riskier” candidate during good weather, when their mood is good, and a “less risky” candidate during bad weather, when their mood is depressed.
A Weather Channel survey in 2012, before the Obama-Romney election, found that bad weather is more likely to discourage undecideds from voting, compared with those who have made up their mind.
“Among those who plan to vote and know which candidate they’ll vote for, 19 percent say bad weather will impact whether they make it to the polls, vs. 35 percent of undecided voters,” the Weather Channel wrote.
A week out, the weather looks fair for election Tuesday across much of the country. Computer models suggest many states will be unusually warm and dry, with the exception of Texas.
If the forecast holds true, candidates won’t be able to blame the weather for low voter turnout.
“Not much in the way of weather will deter voters for this election,” concluded Allan Eustis, meteorologist and author of the historical essay Weathering Elections, Rain or Shine.
(Jason Samenow and Angela Fritz contributed to this post.)