The 121st Boston Marathon has come and gone, and once again temperatures rose above normal, a perennial concern for runners hoping to hit fast times in this historic Patriot's Day race.
When the gun went off for the elite women's race at 9:30 a.m. ET, it was 70 degrees Fahrenheit, and by the time the winner crossed the finish line on Boylston Street 2 hours 21 minutes and 52 seconds later, the mercury had creeped into the low 70's. The average high for Boston in April is 56 degrees F.
Scientific studies have shown that ideal marathon racing conditions range between roughly 40 and 45 degrees F. Warmer weather and higher humidity makes it more physiologically difficult to maintain a consistent pace.
But this year was not an aberration. Last year's starting temperature was also high, hitting 71 degrees F. The 2012 race began at 65 degrees and 2015 at 61. And as scientists have pointed out, high temperatures could be the new normal for this famous race, meaning its days of breaking running records could become much rarer.