Boston Marathon: cool forecast

Race week for the 130th Boston Marathon is lining up cool and mostly dry, with the race set for Monday, April 20, 2026. (baa.org, bostonglobe.com) The Boston Athletic Association says 30,000 participants will race from Hopkinton to Boston on Patriots’ Day, and its official race page lists Monday, April 20, not April 21. (baa.org) Boston Athletic Association race materials say 32,494 entrants are registered, 30,000 are expected to start, and runners represent 137 countries and all 50 states. (rrm.com) The cooler setup follows a warmer week in Boston. The National Weather Service forecast for Logan Airport showed highs near 73 degrees on Monday, 76 on Tuesday, 76 on Wednesday, and 72 on Friday before easing into the weekend. (weather.gov) For runners, cooler air usually means less heat stress over 26.2 miles. WCVB’s marathon weather guide says Boston’s average high for April 20 is 58 degrees and the average low is 43 degrees. (wcvb.com) Boston weather on Marathon Monday can swing hard from year to year. WCVB says the race has seen snow in years including 1907, 1908, 1925, 1961 and 1967, and heavy rain in 1970, 2007, 2015 and 2018. (wcvb.com) Heat has shaped the race too. WCVB says temperatures reached 100 degrees in 1905, 96 in 1976, and 86 in 2004, when officials reported a record number of heat-related illnesses. (wcvb.com) This year’s race will also look different at the start line. Boston.com reported that organizers expanded the field to six start waves, up from four in prior years. (boston.com) The course itself is unchanged: runners leave Main Street in Hopkinton, pass through Ashland, Framingham, Natick, Wellesley and Newton, then finish near Copley Square after Boylston Street. (boston.com) If the forecast holds, the 130th Boston Marathon will start after a warm week and land closer to the cool side of a normal April day in Boston. (weather.gov, wcvb.com, bostonglobe.com)