There's a long-held belief in political circles that the weather affects voter turnout on Election Day - and that rainy, snowy or otherwise bad weather spells trouble for Democratic candidates and helps Republicans. With so many close races across the country, you can bet that pundits on both sides of the aisle will be closely watching the weather reports.

One 2007 study (http://myweb.fsu.edu/bgomez/GomezHansfordKrause_JOP_2007.pdf) published in the Journal of Politics did find that stormy weather on Election Day keeps some voters at home - for every inch of rain that falls, voter participation declines by about 1 percent.

And bad weather may actually be beneficial for Republicans - the study also found that for every inch of rain that falls, Republican candidates receive an extra 2.5% of the vote.

Why? One theory is that some traditionally key blocs of the Democratic voting base - elderly and low-income voters - have a more difficult time getting to polling stations in stormy weather, and are therefore more likely to stay home on Election Day if the weather is bad. This could help explain why Republicans see a bump in their votes when it rains - and why you may hear Democratic strategists praying for sunny skies.

With so many tight races (http://www.foxnews.com/politics/2010/11/01/fox-news-polls-republicans-finish-strong-key-states-eve-election/), every detail counts - including the weather.

"The weather is going to co-operate for much of the country tomorrow as everyone heads for the polls," says Fox News Meteorologist Janice Dean. "We're not expecting any big storms or severe weather to impact large chunks of the country."

This could ease some worries of nervous Democrats facing difficult races. Two of the most closely contested senate races in the Midwest will be in Ohio and Wisconsin. The latest Fox News poll shows Republican John Kasich with a narrow lead over Democratic Governor Ted Strickland, while incumbent Sen. Russ Feingold (D) is facing a surprisingly close battle with challenger Ron Johnson (R) for the senate seat in Wisconsin.

Dean says the Midwest battleground states will be dry and sunny tomorrow, will little reason to worry about the weather. She says the same goes for western states - in Nevada, where Republican challenger Sharon Angle has pulled ahead of Senate Majority Leader Harry Reid, Dean says the forecast calls for "mild temperatures." In Washington, incumbent Sen. Patty Murray (D) leads Dino Rossi (R) by just two points in the latest Fox News poll, and while Dean says it may rain a bit throughout the day, "it's nothing they're not accustomed to."

And in Alaska, where a three-way race between Joe Miller (R), Scott McAdams (D), and GOP write-in candidate Sen. Lisa Murkowski (R) has turned into one of the most closely-watched races of this election, Dean says Alaskan voters, depending on where they live, may face wind, rain and snow - but "certainly nothing out of the ordinary for our 49th and largest state."

On the whole, Election Day weather across the country is likely to be mild, sunny and unlikely to cause any problems. Democrats can relax; perhaps Republicans will want to start praying for rain.