Lauren Ehrler

The Des Moines Register

It's not scientific. It hasn't proven to be an accurate predictor of election results. But it's an Iowa State Fair tradition.

It's the annual WHO-HD Channel 13 "Cast Your Kernel" poll at the Iowa State Fair.

Participation is simple. Fairgoers just head to the local NBC affiliate's tent in front of the Administration Building. If you look 18 you will be given a corn kernel to place in a jar representing either Democratic nominee Hillary Clinton or Republican nominee Donald Trump. You're only supposed to vote once per day and you don't need to be a registered voter.

As of Monday evening, near the halfway point of the fair, Trump was leading Clinton 55% to 45%. (You can check an updating tally of the poll here.) There is no jar available for third-party candidates.

More polling woes for Trump: Clinton ahead in Florida, Virginia

WHO's admittedly unscientific poll runs contrary to the latest NBC poll that shows Clinton ahead of Trump by four points in Iowa.

Ahead of the last presidential contest in 2012, more than 72,000 kernels were cast and fairgoers chose Mitt Romney as the winner with 55% of the vote. We now know that Romney lost and President Obama was elected to another term. In 2008, the poll got it right when Obama edged out John McCain 51% to 49% of kernels cast.

Last summer, kernels were cast ahead of the 2016 caucuses. Clinton swept the Democratic jars and Trump was declared the winner among his Republican challengers. While Clinton went on to win in January, Trump finished second in the caucuses behind Texas Sen. Ted Cruz.

The "Cast Your Kernel" poll has been held at the fair for more than a decade.

Follow Lauren Ehrler on Twitter: @lmehrler