PORTLAND, Ore. — It's nearly as certain as Oregon's rainy season. When there's an election, voters in the state respond with an enthusiasm that's rare in most other places in America.
They did it again this year.
Average voter turnout across the country was horrible during this year's midterms: about a third of those eligible to cast ballots did so, according to AP tabulation of preliminary data from local officials and state election authorities. That's the lowest turnout in at least five decades.
But turnout surpassed 50 percent in a handful of states: Maine, Wisconsin, Colorado, Alaska, Minnesota and Oregon. During each election over the past 10 years, these states have often been among the top performers.
Trying to explain the phenomenon can be elusive. Each state is different — some lean Republican, some lean Democrat, for example — and experts say there's no precise equation that results in higher voter turnout. A few things, though, do tie Oregon to its fellow high voter turnout states: A century-old tradition of civic-mindedness that dates to the progressive era, convenient voting procedures and especially contentious races or ballot issues.
"There is something about our civic culture in this state that rewards civic participation of all kinds," said Minnesota's recently elected secretary of state, Steve Simon. "We are doers and joiners and voters in Minnesota."
The states with consistently high turnout tend to make it easy to cast ballots. Maine, Minnesota and Wisconsin allow voters to register on Election Day. Colorado, Oregon and Washington state hold elections exclusively by mail.
Though experts say convenience alone doesn't necessarily mean higher turnout, in Oregon, residents like voting by mail. Ballots are sent by mail to registered voters three weeks before the election, and voters can take time making their election choices. Filling in ballots at the dining room table has become an Oregon tradition.
An especially contentious race or ballot issue also drives voters to weigh in, and this year, several of the top voter-turnout states had closely watched races.
Wisconsin has long been a battleground state in presidential elections, and most recently, it's had a string of hotly contested campaigns following Republican Gov. Scott Walker's push to weaken bargaining rights for public employee unions.
"People see their votes as making a difference," said Kevin Kennedy, Wisconsin's chief elections official. "The fact that it's had a very sharp partisan divide the past few years probably focuses to engage voters."
Maine's turnout this month was boosted by contested races for governor and U.S. House, said Maine Secretary of State Matthew Dunlap. And it also got a bruin boost. A ballot question that sought to ban the use of dogs, bait and traps to hunt bears drew out residents in rural parts of the state in large numbers to vote it down.
Oregon voters also turned out in droves to vote on a ballot measure asking whether they wanted to legalize recreational marijuana. It drew 40,000 more votes than the hotly contested race for governor.
It was nothing new. Oregon has a long history of contentious ballot measure fights over taxes, property rights, crime, abortion and a host of other topics. They've been used to enact many a law that has given Oregon a reputation for having no fear of going its own way, such as a statute allowing terminally ill people to hasten their lives through the use of doctor-provided medication.
The fervor for ballot measures and the enthusiasm for voting is a legacy of the state's embrace of the progressive movement in the early 20th century, which was also active in other states with high voter turnout, said Jim Moore, director of the Tom McCall Center for Policy Innovation at Pacific University outside Portland.
Oregon was among the first states to let women own businesses and keep their money. It allowed women to vote before the 19th Amendment extended the right nationwide. And it gave citizens the ability to go around their elected leaders and take a direct role in making laws.
"It was putting power in the hands of the voters and it's basically continued over the last 100 years," Moore said.
Associated Press senior research coordinator Cliff Maceda in New York City, AP writers Rachel La Corte in Olympia, Washington; Kyle Potter in St. Paul, Minnesota, and Alanna Durkin in Augusta, Maine, contributed.