Over the past 10 years, Boston Marathon runners have faced temperatures ranging from 7\u00b0C (44\u00b0F) on cooler years to 18\u00b0C (64\u00b0F) in warmer editions. The median temperature of 12\u00b0C (53\u00b0F) puts this race in the neutral category for running conditions.
Wind speeds average 17 km/h during race hours, with peak gusts reaching 26 km/h in challenging years. Humidity sits around 59%, and there is a 30% chance of rain on race day.
These conditions translate to an estimated pace impact of +3.1% compared to ideal running conditions. For a 4-hour marathoner, that means roughly 7 minutes slower than a perfect-weather day.