Will L. Fletcher '12 chats with his supporters and friends after finishing the Boston Marathon early Monday afternoon, which he ran to support the South Boston Boys and Girls Club.

Temperatures approaching 90 degrees did not deter dedicated Harvard marathoners, who raced the 26.2 miles from Hopkington, Mass., to downtown Boston on the hottest April 16 in recorded Boston history. Harvard students and faculty, some participating for the first time and others well-versed in the event, stepped up to the starting line at 9 a.m.

While some were focused on beating personal goals, others were simply trying to cross the finish line in the extremely hot weather.

Daniel E. Lieberman ’86, a professor of Human Evolutionary Biology who has done extensive research on running, ran his second Boston Marathon on Monday, finishing in 4 hours and 19 minutes, his slowest time ever.

“It was brutal conditions for a marathon,” Lieberman said. “Any marathon is challenging, but today’s was especially challenging.”

Lieberman said that he felt the heat had a significant impact on the race.

“I saw a lot of people in medical tents and I saw a woman collapse at the end,” he said. “If it hadn’t been for all the people on the side with ice and water, I wouldn’t have made it.”

Along with handing out ice and water, the crowd sprayed contestants with water hoses and splashed runners with cold liquids.

Stephanie Choi ’13 ran her fifth marathon—and her third Boston Marathon—in four hours and three seconds. She said that she “definitely ran slower” because of the heat.

“My time was around 30 minutes slower,” she said. “A lot of people around me were puking or needed medical help, so I was just glad that I finished.”

However, not all runners felt the heat was a major obstacle. William L. Fletcher Jr. ’12, who ran his first marathon on Monday, said the heat did not really bother him, although he did “take advantage of some ice.”

For Fletcher, the marathon was about more than just personal achievement. His marathon efforts raised $5,000 for the South Boston Boys and Girls Club. Fletcher said a major factor in his decision to run was the feeling of the clock ticking on his time at Harvard.

“It was really something I wanted to do before I graduated,” Fletcher said.

Fletcher, who ran the marathon in just over four hours, said that he enjoyed the entire race despite the intense heat and noted that he was especially encouraged by the energy of the crowd.

“It felt good the whole way through and felt great at the finish, but the best part was all the fans and everyone cheering you on the whole way even if they didn’t know your name,” Fletcher said. “It was really inspiring and motivational.”

Ali E. Evans ’13, who ran the race in about four and a half hours and reached his personal goal, echoed Fletcher’s sentiments about the “super supportive” crowd.

Evans, who took up running to fill the void left when he quit Harvard football, emphasized the benefits he said that he attained from training for and running in the marathon.

“I think running a marathon­—it’s not for everyone—but it’s a great experience to get you a lot of discipline, to overcome challenges,” Evans said.

—Staff writer Mercer R. Cook can be reached at mcook@college.harvard.edu.

—Staff writer Maya S. Jonas-Silver can be reached at mayajonas-silver@college.harvard.edu.