Election Day in New York City was a scorcher. Temperatures at Kennedy Airport reached 102 degrees last Tuesday, making it the city’s hottest June day since 1948. Average June temperatures in Central Park rarely exceed 75 degrees. The recommendation for vulnerable groups—usually the elderly or chronically ill—was to stay inside during the heat wave.

But for civically-minded New Yorkers, that advice was impossible to follow as polls opened for voters in the primary elections in the city. 

The heat also got the attention of elected leaders in the state. “The NYC Board of Elections is not equipped to handle the heat wave,” wrote U.S. Rep. Gregory Meeks (D-N.Y.) and New York State Assembly Member Rodneyse Bichotte-Hermelyn in a joint statement they issued four days before the primary. 

Leading up to election day, the New York City Board of Elections planned to install fans and distribute water at all polling sites. But Meeks and Bichotte-Hermelyn said that the plan was “not sufficient to sustain a healthy and safe environment” for voters “showing up in person on Election Day.”

They felt the plan lacked protections for “commonly disenfranchised communities of color,” those who are most impacted by the urban heat island effect. It’s to be seen if the heat wave substantially affected voter turnout in these neighborhoods. But extreme heat events are increasingly stressing elections both in the U.S. and abroad. 

Climate change is shifting the distribution of hot temperatures during the calendar year, starting summer heat earlier and ending it later, and increasing the frequency of extreme heat events. And the impacts on electoral processes will increase with the temperatures. 

The effects of extreme heat on elections are not just felt on the days that polls are open. Heat impacts everything from campaigning to the management of polling sites, as well as the act of voting. This is forcing municipal bodies to rethink how they can safeguard electoral processes.

Elections Heat Up Around the World

The New York City elections were not unique in their extreme heat exposure, said Ferran Martinez i Coma, a professor of government and international relations at Griffith University in Brisbane, Australia. During the June 2024 national election day in Mexico, multiple states reached a blistering 105 degrees—almost five degrees hotter than the expected maximum temperature that day. And in July 2023, 104 degree heat bore down on the Spanish national election. 

“Twenty years ago, this didn’t happen, or happened way less often,” he said. “Now this is happening more often, and it’s affecting many more countries.”

But scorching temperatures on election day is only one part of the problem, Coma stressed. Extreme heat impacts three distinct groups during election season: the candidates, the poll workers and the voters. Each of these groups is affected differently, and at different parts of the electoral process.

In order to inform and try to activate voters, political parties and their candidates often knock on doors in the communities they want to serve or hold rallies for their base. Outdoor rallies, in particular, can threaten both prospective voters and candidates with heat illnesses. At a rally in Arizona for the presidential candidate Donald Trump in June 2024, 111 degree (44 degrees Celsius) temperatures sent 11 people to the hospital.

“The candidates, they are humans as well,” he said. “At some point they can even get sick.”

Swinging Temperatures Can Swing Elections

In parliamentary systems, where prime ministers or members of parliament dictate when elections take place, extreme heat starts to pose both safety and ethical questions, Coma said. If the ruling party in a parliamentary system recognizes that the opposition’s voter base is likely to be in the heart of an impending heat wave, it could be politically advantageous to hold the election when the temperatures are peaking.

“Some people will say, ‘well, those are the rules of the game,’” he said. “In some other countries, the [members of parliament] take advantage of the natural hazard to their own advantage.”

In the U.S., where federal or local laws set the dates for elections, this type of political manipulation of when votes are held can’t occur. But the lack of legislative flexibility around elections has its own issues.

Having elections tied to a specific month or season (November for federal elections in the U.S.) eliminates weather-related advantages an incumbent party might have in campaigning or the timing of the opening of polling places. Instead, the focus is often on poll site management to make the election resilient to the weather.

Dealing with extreme heat at polling sites on election day is really about being proactive, said Alina Garcia, Miami-Dade County supervisor of elections. In Florida, which has the second highest percentage of residents over the age of 65 in the nation, getting people out of the elements is a priority.

Poll sites in Miami-Dade County try to maintain adequate indoor space so that voters can wait inside—out of the sun and in air conditioning, she said. If that space fills up, voters can take a number to hold their place in line and return later. Miami-Dade also has early voting and voters can request a mail-in ballot, if necessary, she said. This allows voters to avoid exposing themselves to dangerous heat altogether. 

But early voting may not spare the election system—or voters—from a weather related crisis, said Sarah Birch, professor of political science at King’s College London. While the bodies that manage elections can warn voters to avoid dangerous weather by casting their ballots before an oncoming heat event, that could inadvertently bottleneck the polling site, she said. 

“The problem is, in your typical early voting system, they’re just not going to have the staff available,” she explained. “There’s not going to be a set up to cater for a huge rush of voters two days before.”

Protecting Voters and Poll Workers

Fully vote-by-mail systems have been considerably more climate resilient than other methods of managing voting during heat waves. King County, Washington, has been fully vote-by-mail since 2009. King County residents receive their ballots, without request, about three weeks before any election, Halei Watkins, communications manager for King County elections, said. 

The system’s relatively long track record of success has nearly eliminated in-person voting, and that has shifted the focus of heat protections from voters to poll workers. If it’s forecast to be incredibly hot, Watkins said, King County will shift ballot collection schedules so that workers “start more at like 5 a.m. rather than 7 or 8 a.m. so they can get out and pick up ballots from drop boxes before it gets really hot out.”

Such precautions can make a big difference in health, safety and effectiveness of poll workers, as most of them are middle-aged volunteers who are more susceptible to heat exposure than younger people, said Birch at King’s College.

And, for people working long hours at voting sites, the consequences of extreme heat exposure can be severe. In spring 2024, heat waves baked large parts of Western and Northern India. Temperatures approaching 130 degrees (54 degrees Celsius) were recorded in New Delhi during the height of the general election season in June. At least 33 poll workers died in the state of Uttar Pradesh as a result of the heatwave.

Extremely dense municipalities, like those in India, have a much harder time shielding voters and poll workers from heat than places like Miami. Additionally, adequate funding is a prerequisite for implementing safety strategies. Air conditioning, fans and potable water from taps or in bottles all have a price tag attached to them. And those prices start to rise quickly during heat waves as demand for cooling supplies, like air conditioners, rise with the temperature.

“The governments that are trying to fund this are cash strapped,” Birch noted.

Because the funding isn’t always there to make election services or polling sites heat resilient, most countries only address the impacts of extreme weather on voting following a catastrophe, she added. And a voting system can only be as proactive and nimble as the law—or lawmakers—allow. 

In 2021, Georgia lawmakers passed an election law that included a ban on the distribution of water in polling lines. A lawsuit from several civil rights and voting rights groups challenged the law, saying it infringed on the right of free expression by banning food and water distributions near voting centers, as well as requiring birth dates printed on absentee ballot envelopes. In 2023, a federal judge narrowed the law to allow for food and water distribution within 150 feet of a polling site. Up until last week, distributing water at polling sites was also illegal in New York, but Gov. Kathy Hochul signed legislation repealing a 1992 election law that made water distribution in election lines a misdemeanor.

“Providing water to voters waiting in line is a common-sense way to ensure New Yorkers have an easy, safe and secure experience in the voting booth,” Hochul said in a press release.

While American laws like these are starting to change in response to the stress that global warming is placing on the electoral system, some climate impacts on elections will demand more drastic responses. In 2012, flooding from Hurricane Sandy left polling sites in various parts of New York and New Jersey destroyed or unusable. Heat waves have rarely broken down the actual infrastructure needed for voting. 

“Some people consider, ‘well, should we be able to delay some elections?’” Coma said. “You can think about it if there are floods, but no offense, we can’t delay elections because it’s hot.”