GRAND RAPIDS, Mich. (WOOD) — It’s going to be a busy weekend in Grand Rapids as thousands of people head to the city for the 20th annual Grand Rapids Marathon.

The Kids Marathon starts at 1:30 p.m. Saturday. Then, the main races — including the half and full marathons, 5K and 10K — are on Sunday.

“The race will happen, no matter what the weather,” Don Kern, race director for the University of Michigan Health-West Grand Rapids Marathon, said. “We live in Michigan. We’re used to everything.”

Despite the heavy rain, Kern said over 3,500 runners have signed up.

“We’re excited about it,” he said. “All the preparations are going well. Most of our staff have been on staff for a very long time, so we’ve kind of got it dialed in. Things are working like they’re supposed to.”

Kern said there’s only one spot throughout the entire route that could potentially be tricky for runners if the rain continues. It’s located just past John Ball Park, heading out of town near Butterworth Street.

“One spot on the road, that if it rains a lot, will have kind of a river going over it,” he explained. “Anybody who’s run the River Bank Run before has run through that if they’ve run the River Bank run a few times. We had a little bit in 2017 there. We’ve got guys out there with blowers and kind of draining the swap for us out there.”

The marathon starts and finishes at the David D. Hunting YMCA located in downtown Grand Rapids, then heads southwest through Millennium Park.

“The nice thing about it is, we kind of get the congestion out of town in a big hurry,” Kern said. “We do a loop through town first thing, and then we head out to Millennium Park and out to Indian Mounds Road and enjoy the stuff out west. All the fall colors are out and they’re gorgeous right now.”

The Grand Rapids Marathon started in 2004, according to Kern. He said during the first year, 930 people signed up.

“It just kept growing from there,” he said. “We knew right then we had a thing going in Grand Rapids, and so here, it’s our 20th year. And we’re looking forward to another 20, 40 or 60, or whatever it’s going to be.”

For more information on the race, you can visit its website.