The annual Twin Cities marathon has been canceled due to record-breaking heat in Minneapolis and St. Paul, marathon organizers announced Sunday morning.
The event, slated to begin at 7 a.m. local time, was expected to draw 300,000 spectators, according to the organizers.
Temperatures were forecast to reach an unseasonably high 91 degrees Fahrenheit, according to the National Weather Service. The average high for the Minneapolis-St. Paul area around this time of year is around 66 degrees.
"We're sad we have to make this decision, but we knew it was the right one," Charlie Mahler, communications manager for the race, told CNN's Omar Jimenez and Amara Walker on Sunday.
"The latest weather forecast update projects record-setting heat conditions that do not allow a safe event for runners, supporters and volunteers," organizers said in a statement.
"The safety of participants and the community will always be our primary concern," the statement said. "Extreme heat conditions can tax both runners and our emergency medical response systems."
The organizers had been monitoring weather conditions for several days as the heat continued to rise, Mahler said.
"I think there's a range of emotions for runners. There are probably some that are relieved that we made the decision for them. I think there are others that think it's in all in your head and I can run in these difficult conditions," he said.
Organizers kept the community up to date as they monitored the situation, and the race was still on as of Saturday night.
"We have an extensive protocol as we're heading into a race," Mahler said, "We knew early on the week of this race that we were facing warm and humid conditions."
"Overnight, the forecast conditions got even worse and that's how we had to make the call in the early hours of the morning," he added.
Matt Anderson was set to run the race when he received note of the cancellation early Sunday morning. Anderson told CNN affiliate WCCO he linked up with a group of fellow runners who have decided to run the race despite the official cancellation.
"I understand safety reasons, got to make the right decision. But for me, I want to keep running today anyway" he said.