A warm and sunny day is on tap for Marathon Monday
The 121st running of the Boston Marathon will be a warm and sunny one, with highs in the lower 70s – perfect weather for spectators, but a bit on the warm side for runners pounding 26.2 miles of pavement.
Temperatures were already in the mid-60s by about 8 a.m. as runners descended upon the race course. It will be mostly sunny all day, with highs ranging from 64 degrees in Hopkinton to 73 degrees at the finish line.

A look at high temperatures across the Boston area on Marathon Monday.
Relative humidity is going to be very low. This is important because it will help wick the sweat off runners’ bodies and cool them down. This also means water loss will be high, so be sure to use those water stations.
Winds are going to be favorable for runners this year. I expect we might even see a record or two fall because of the northwest wind. The wind direction isn’t exactly perfect, but it’s pretty close. While there’s often a head wind for runners as they pass Newton and head into Boston, this year the wind will be at participants’ backs the entire way. The wind will be consistent and help guide them to the finish line.
Of course, the same weather runners and spectators will enjoy will also overlook Fenway Park during the traditional Patriots’ Day game. Other celebrations taking place during the day can count on cooperation from Mother Nature as well.
Follow David Epstein’s forecast on Twitter @growingwisdom.