( CNN ) -- Presidential candidates have been wooing voters in Iowa for months , but who wins Thursday may simply come down to where the caucus-goers live , where they meet and the weather . Iowa is a mixed bag politically , and one of the most evenly divided states in the nation . But the candidates will likely watch two regions more closely than others . The central part of the state -- including industrial Des Moines -- is Iowa 's most Democratic area . Western Iowa , on the other hand , is home to the most Republicans -- especially the rural counties in the northwest . The Mississippi River city of Davenport is expected to be one of the most significant battlegrounds , with Linn County -- dominated by the university town of Cedar Rapids -- also attracting lots of attention from both parties . Past Iowa caucuses have been nail-biters for the candidates . Democrat Al Gore won the state by a margin of just 0.3 percent in 2000 , while President Bush carried it in 2004 by 0.7 percent . In fact , Bush was the first GOP presidential candidate to carry Iowa in 20 years . Important endorsement . The support of Iowa 's largest newspaper , the Des Moines Register , may also play a role in Thursday 's caucuses . The paper 's presidential endorsements began in 1988 and have become a highly sought-after prize in Iowa presidential politics . George W. Bush was the Register 's pick in 2000 and went on to win Iowa , the GOP nomination and the White House . Republican presidential hopeful Bob Dole won the state in 1996 and 1988 after receiving the paper 's support . Democratic candidates have n't had as much success with the Register 's endorsement . John Edwards finished in second place in Iowa in 2004 , while Paul Simon was also a close second in 1988 . The paper endorsed Sen. John McCain and Sen. Hillary Clinton for their respective parties ' nominations . The candidates have to appeal to voters with strong opinions . On the Republican side , 37 percent of participants in the 2000 Iowa GOP caucuses identified themselves as members of the religious right and 73 percent described themselves as conservatives . Meanwhile , 56 percent of the participants in Iowa 's 2004 Democratic caucuses described themselves as either very or somewhat liberal . About 37 percent said they were moderates . The weather . Iowans who take part in the caucuses must traditionally brave freezing temperatures and lots of snow . Presidential candidates know bad weather may affect how many people turn out , but 1972 was the only time rough winter conditions played a role in the caucuses , according to Drake University 's Hugh Winebrenner -- the nation 's leading expert on Iowa caucus history . Caucus-goers that year encountered heavy snowdrifts from a blizzard the previous day . Temperatures dipped below zero across most of the state . The weather forced about one-fourth of Iowa 's 99 counties to postpone their Democratic caucuses up to two days after the scheduled date . The forecast for Thursday is much better . Temperatures will be in the 20s during the day and dip just below that as the caucuses begin , according to the Des Moines Register . E-mail to a friend .
The central part of Iowa is the state 's most Democratic area . Western Iowa is home to the most Republicans . Support of Iowa 's largest newspaper , the Des Moines Register , highly sought . Weather may affect how many people turn out .