The Boston Marathon is always challenging — it’s supposed to be — but the unforgiving weather thrown at the runners Monday made the historic course a punishing gantlet of biting rain, buffeting headwinds, and dispiriting cold.
By comparison, even Heartbreak Hill was only a molehill of misery.
“I’ve never run in anything like that before,” said Matthew Gonnella, a 25-year-old Suffolk Law student running his first Boston Marathon and fourth marathon overall.
Simply running the Marathon is the ultimate prize for thousands of athletes who train for months in near-anonymity to compete here. But thinned crowds along the course, coupled with the harsh conditions, doused much of the traditional excitement from Hopkinton to Boston.
Blame a meteorological trifecta of headwinds gusting to 35 miles per hour, more than half an inch of steady rain, and 40 degree temperatures.
More than 2,500 runners, including 25 elite athletes, received medical treatment, race organizers said. Eighty-one runners were taken to the hospital.
Andrew Roach, a 40-year-old from Baltimore, set this goal for such a day: “Not to get hypothermia.”
As it was, volunteers watched thousands of hardened competitors cross the finish line soaked, and in some cases dazed, by the pounding they had endured.
“There was no way around it,” said Gonnella, of Syracuse, N.Y. The first five miles were easy enough until a “switch flipped” in the clouds somewhere, unleashing torrents of rain, he said.
In the past 15 years, just a few Boston Marathons could compare in terms of unfavorable weather. There were the 2004 and 2012 races, which featured temperatures in the mid-to-high 80s at the finish. And there was the 2007 run, with rain and headwinds of 30 miles per hour.
Only the 1976 race — the infamous Run for the Hoses, with temperatures in the mid-90s at the start — might have had more extreme conditions.
Stuart Kolb reached the finish, completing his 100th marathon on his 56th birthday. But his eighth race in Boston earned a less favorable distinction.
“This was the wettest,” said Kolb, of Green Bay, Wis. “I’ve run in some wet marathons, but never from start to finish with no breaks. It didn’t matter if it was a sprinkle or a driving rain, it never stopped.”
In Wellesley, more than 50 runners streamed into Carter Memorial United Methodist Church, which threw open its doors to become a makeshift recovery site offering food, drinks, coffee, and a roaring fire.
At least the runners were moving. Not so for a 26.2-mile line of miserable spectators.
“This is the worst I’ve ever seen,” said Corey Hanrahan, 37, a visitor from San Diego who cheered on the runners in Newton. “This is brutal.”
On Sunday, Jim Pathman was running on a beach in Hawaii. On Monday? The 53-year-old stood with Hanrahan on Heartbreak Hill as rain and heavy winds threatened to rip the tent from over his head.
“I’m happy not to be running today,” said Pathman, who has five Boston Marathons on his resume. “You always want to run it, but this is the perfect year not to.”
Darcie Schoenfeldt-White, a spectator in the Back Bay, said she relied on plenty of layers, cup after cup of coffee, and “lots of prayers” to get through the rain before her friend, Sara Mehler, reached the line.
“I wouldn’t be anywhere else,” said Schoenfeldt-White, 36, of Meadville, Pa. “I missed two of my kids’s birthdays to be here. But I told them I had to be here for her. They get it.”
At Wellesley College, where students have long greeted runners with a wall of noise, only a thin but enthusiastic group stood behind a barricade as the first runners streamed by. Students living in Munger Hall spent weeks making 533 signs to encourage the runners. But within a few blustery, rainy minutes, most of them had turned into multicolored pulp.
Ava Mackay-Smith, looking at one sign wadded on the ground even as she hung fresh ones, said she thought runners would still get the message of support.
“They need energy to keep going, and we’re going to give it to them,” the sophomore said.
Nearby, a California family stood under a tree, wearing plastic ponchos as they awaited a relative at the halfway mark.
The family had misunderstood the meaning of the Wellesley College “scream tunnel,” which, to their regret, did not provide actual shelter.
“When you hear ‘tunnel,’ you think you’re going to be underneath something,” Dianna Hawkins said. Still, her mother, Lynn Geiszler, said the students’ enthusiasm was a welcome distraction from the cold and wet.
“The excitement outweighs the weather,” she said.
At normally festive Hopkinton Common, Kathryn Curry began to pack up her cowbells and paint markers around 12:30 p.m., 40 minutes after the last runners took off for Boston.
In good years, the town resident and avid runner sells well over 100 brightly colored bells, mostly with Boston Marathon motifs and phrases like “Got Hills?” and the Citgo sign. On Monday, though, she moved just 25 bells, to 15 customers, over six hours.
“I’ve never seen so few people at the start of the Marathon, ever,” Curry said.
Tedy Bruschi, the former New England Patriots star, encouraged runners from a perch at the start and playfully ribbed Mother Nature and the Red Sox, whose game was cancelled by the weather.
“They might not play baseball, but we run” in weather like this, and play football, too, he said.
On Heartbreak Hill, Orlando Diaz was still seeking his first customer more than two hours after setting up a small sausage cart early Monday morning. “Every year, it’s always packed,” said Diaz, whose sales were undone this year.
Still, he persevered under two sweat shirts, a jacket, a poncho, and another quick-heating option: the flames of the nearby grill.
“My hands, I just put them over there and toast them up,” Diaz said.
Like Diaz, many spectators proved to be as hardy as the runners. One of them, 24-year-old Cassi Delatorre of Silver City, N.M., waited at the finish line to greet her husband, Xavier, and announce that she is seven weeks pregnant with their third child.
To do it, she hoisted this sign: “A new little runner is approaching the finish line, December 2018.”
Carlos Arredondo, a hero from the 2013 Boston Marathon bombings, also ran the race — for the first time — in honor of his sons and Boston Police Officer Dennis Simmonds, who died in 2014 from injuries he suffered during the chaotic firefight with the Tsarnaev brothers in Watertown days after the bombings.
As he crossed the finish line, the 57-year-old said, he savored the moment and also recalled rushing to the aid of bombing victims, including Jeff Bauman, who lost his legs in the blasts.
“I wanted to cheer this amazing moment and also remember the one . . . from that terrible day,” Arredondo said in a pelting rain.
He then looked down and held up the medal that had been draped around his neck.
“Look at that,” Arredondo said, a smile spreading across his face. “What a country.”Dugan Arnett, Jerome Campbell, and Andy Rosen of the Globe staff contributed to this report. Brian MacQuarrie can be reached at firstname.lastname@example.org. Eric Moskowitz can be reached at email@example.com. Follow him on Twitter @GlobeMoskowitz. Matt Stout can be reached firstname.lastname@example.org. Follow him on Twitter @MattPStout.