The toughest year I ever ran Boston was 1982, the year that Alberto Salazar and Dick Beardsley ran "The Dual in the Sun". It was a totally cloudless day, with temps getting up to around 70-degrees. In those days the race started at noon, so we ran the bulk of the race in the heat of the day. For whatever reason I managed to survive the heat pretty well, which meant I was passing people steadily over the second half of the race. That year I finished 351st. The next year, under almost ideal conditions, I ran four minutes faster, but finished over forty places further back in 393rd.
Those conditions were gentle compared to what the runners had to contend with this year. One of my buddies, John Dean, sent me this comment: "I've never been more wet in my life with all of the water bottles, cups, hoses, etc. available during the race, but it still wasn't enough to overcome the heat. Body just runs inefficiently in 80+ temps. However it was fun because you felt like you were a part of some sort of "epic" survival drama. Crazy stuff."
John Jay had three finishers that I know of. Liam Harrison ran an amazing race under those conditions, finishing under three hours in a time of 2:58:08. Laura McCloskey flew across the country to run and ran a very smart, even paced race. She finished in 3:54:53. Sally Briggs, who is also doing lots of triathlon training, finished in 3:48. All three of them had trained very hard for Boston and were ready to run much faster than their finishing time. That's one of the downsides of running a marathon. You can spend months doing everything right. Then the weather is crazy and it all goes out the window.