PORTAGE LAKES, Ohio -- Grab your bathing suit, flip-flops and get ready to dive in!

It’s time for the 13th annual Portage Lakes Polar Bear Jump.

565 people, ranging in age from 9 to 81, have pre-registered to plunge their bodies into the frigid Portage Lakes on Saturday. Pre-registration closed Tuesday.

What began as a small, back yard charity event has become one of the largest polar bear jumps in Northeast Ohio.

NOTE: Video below shows highlights from the 2015 event.

“Eventually it outgrew our yard and we had to move to the state park,” says Heather Pariso, the Portage Lakes Polar Bear Club Secretary co-founder.

To date, the annual Portage Lakes Polar Bear Jump has raised more than $600,000 for various charities since it first splashed to life in 2004.

In 2016, the frigid jump will benefit the Ronald McDonald House and Camp Quality Ohio. So far, this year’s event has raised roughly 35 percent of the $100,000 goal. Organizers note the pre-registration tally does not include on-site donations or jumpers who register to participate day of.

While the water will be wickedly chilly, the actual air temperature will be more spring-like as the mercury creeps into the 50s with sunshine Saturday.

FORECAST | 7-day outlook

“With the expected warm weather, this is the perfect opportunity for all of you ‘chilly chickens’ to come out and jump on Saturday,” Pariso says.

It’s a $25 minimum to register. $100 donors receive a free T-shirt.

The jump begins at 2 p.m. at the Portage Lakes State Park beach, which is located at 5031 Manchester Road. Those jumping are asked to arrive at noon. Too afraid to take the plunge? Onlookers are invited to pack the beach to watch the wackiness unfold.

WKYC app users can see two photo galleries from the 2015 Portage Lakes Polar Bear Jump HERE and HERE.

Below you will find a breakdown of how much the Portage Lakes Polar Bear Jump has grown through the years:

2004: 74 jumpers. Temperature was 57 degrees.

2005: 104 jumpers. Temperature was 35 degrees.

2006: 145 jumpers. Temperature was 10 degrees.

2007: 160 jumpers. Temperature was 28 degrees.

2008: 210 jumpers. Temperature was 33 degrees.

2009: 220 jumpers. Temperature was 40 degrees.

2010: 400+ jumpers. Temperature was 35 degrees.

2011: 400+ jumpers. Temperature was 34 degrees.

2012: 750+ jumpers. Temperature was 33 degrees.

2013: 750+ jumpers. Temperature was 27 degrees.

2014: 800 jumpers. Temperature was 45 degrees.

2015: 700+ jumpers. Temperature was 27 degrees.