Grandma's Marathon, a popular spring-summer bookend to autumn's Twin Cities Marathon, said Monday it had record first-day registration of almost 10,000 runners for next June's marathon and half-marathon.

Grandma's opens registration for its marathon and half-marathon Oct. 1 every year — coincidentally, this year, the same day the Twin Cities Marathon was canceled because of intense, record heat in the forecast.

"We're supposed to piggyback on a successful and fun day for everyone [at the Twin Cities Marathon]," said Grandma's marketing and public relations director Zach Schneider, who was in the metro volunteering for Twin Cities in Motion, the marathon organizer. "Unfortunately it didn't happen like that."

Schneider acknowledged that the Twin Cities Marathon cancellation might have factored in the high registration numbers.

Last Oct. 1, Grandma's saw 5,507 registrations between 7 p.m. — when registration opened — and midnight. On Sunday, Grandma's had almost 4,000 more (9,450) sign-ups for its marathon and the Garry Bjorklund Half-Marathon, Schneider said, and the numbers were rising Monday morning.

Grandma's has a cap of 9,000 runners; the half-marathon, 8,000. Monday morning, the half-marathon already had 6,000 runners.

Schneider said the high interest isn't unexpected, owing to favorable weather in recent years in Duluth and more normalcy in the wake of COVID-19's impact.

"We expected to see a surge because of the good years of running weather, but there probably was some added interest," said Schneider, referring to Twin Cities Marathon events runners.