Complete list of US weather warnings for Election Day

Meteorologists with the National Weather Service (NWS) have issued weather warnings across the country as millions of voters head out on Election Day.

As of Tuesday morning, winter storm warnings and watches stretched from Montana to New Mexico. Critical fire conditions accompanied by strong winds plagued the California Bay Area, and a deluge of flood-triggering rains continued across the central United States. To the south, tropical storm warnings were issued for Florida's coastal waters as Tropical Storm Rafael approached.

Rain and snow are expected to have the biggest impact on turnout, although the worst storms are expected to avoid the seven swing states that could determine the winner of one of the closest presidential elections in U.S. history.

The worst of the winter weather — including winter storm warnings and storm warnings — is expected in Montana and Wyoming, traditionally red states that former President Donald Trump is unlikely to lose even if turnout drops because of the bad weather. Likewise, windy conditions in California are unlikely to impact Vice President Kamala Harris' expected success in the Golden State, despite multiple warning signals and power shutdowns in California to guard against wildfires.

Previous forecasts suggested possible rain and snow in the swing states of Michigan and Wisconsin, but no weather warnings had been issued as of Tuesday morning. There was no bad weather in other swing states, including Pennsylvania, North Carolina and Georgia. The only weather warnings for Nevada and Arizona included a wind warning and a freezing warning.

Republican strategist Mark Weaver previously said this Newsweek that voters are particularly passionate about the presidential candidates this year, meaning bad weather, barring a blizzard, is unlikely to stop them from voting, especially since nearly 80 million people have already voted early or by mail.

However, some of the worst storms could impact voter turnout in key Senate and House races, particularly in Montana.

Winter storm in Montana could deter voters

Montana has a tight Senate race between incumbent Jon Tester, a Democrat, and Republican Tim Sheehy. Tester, who has narrowly retained his seat since 2006, is the only Democrat to hold a statewide congressional office in Montana. With winter storm warnings across the state, the weather could convince voters to stay home, especially those who live in mountainous areas.

“Traveling could be very difficult to impossible and some vehicles may require snow chains. Anyone staying in the backcountry should ensure they are prepared for hazardous conditions,” the winter storm warning states. “Widespread snowdrifts could significantly reduce visibility. Strong winds could cause damage to trees and power lines.”

Multiple studies have found that while bad weather has always affected voter turnout, it tends to benefit Republicans, particularly in presidential elections.

“In addition to its direct effects on voter turnout, we showed that bad weather can influence election outcomes by significantly reducing Democratic vote share in presidential elections, benefiting Republicans,” one study said.

On Tuesday morning, the latest update from poll aggregator FiveThirtyEight showed Sheehy polling nearly seven points ahead of Tester.

Wildfire conditions in California

Although Harris is expected to win California, the U.S. House race for California's 45th Congressional District is not as certain.

There are multiple NWS warnings in place for the region, including a red flag warning. Critical fire conditions have prompted Pacific Gas & Electric (PG&E) to call for public safety power shutoffs further north in the Bay Area, although the voluntary shutoffs are unlikely to impact power in the battleground 45th District, where Republican Rep. Michelle Steel Derek Tran meets the Democrat. Steel defended her seat by nearly five points in the 2022 midterm elections, but recent polls this year show Tran in the lead.

Further north, PG&E spokesman Jeff Smith said Newsweek If power outages occur at two Bay Area polling locations, the voting centers have been equipped with backup generators to ensure voters are not disrupted. None of the state's tabulation centers are affected by the power shutoffs, although PG&E has deployed backup generators there as well out of an abundance of caution.