Dan Pelkey has competed in the Blaine Triathlon each year since it began in 2012. But last year, if the 51-degree water in Sunrise Lake had been just one degree colder, the swim portion would have been canceled, Pelkey said.

This year, the competition in which racers swim, bike and run will be on the move itself — switching from May to September — in hopes of avoiding that kind of chilling water.

"We've had such cold springs and the water [temperatures] have been so cold we've almost had to cancel the swimming leg," said Nate Monahan, the race's director. "[Participants] were not very excited about jumping in in their wet suits when it was 50 degrees."

Last year, Monahan said, was right on the edge, and too close for comfort.

The 2015 triathlon will be held Sept. 12, the Saturday after Labor Day. Monahan said he expects anywhere from 350 to 400 participants. Last year's competition drew about 220.

"Even if it cools down in September, it won't be as cool as it was [in May]," said Pelkey, a Blaine police officer.

Monahan confirmed that, saying Sunrise Lake's temperature in September is usually around 65 degrees.

Pelkey said the Blaine Triathlon has a strong following because of its flat course, but the unpredictable weather was the final thing that needed to be addressed.

"It's well put together, but I think that last factor that needed to get dialed in was the date," he said. "Some Mays you can be out in a T-shirt, and some May's you can be in snow gear because it's snowing. You just never know what you're going to get in May."

The three-part race consists of a .3-mile swim, a two-loop, 16.7-mile bike ride and a 3.5-mile run.

Another advantage to the date change, Monahan said, is that the competition is now one of the last of the triathlon season, and the course lends itself to career-best races.

"[The course] is very flat. It could be your last course of the year and you could set a career best," he said.

Taylor Nachtigal is a University of Minnesota student reporter on assignment for the Star Tribune.