Weather Predictions for the Boston Marathon

Being just a few days away from one of Boston’s most iconic annual events, we begin to look at what conditions will be like for the famous Boston Marathon. After getting out of what felt like a long period of rain and clouds we finally get some summerlike conditions for the race with a warm clear day around the city. For the start of the race out of Hopkinton we are looking at temperatures in the low 50’s with light Northwest winds between 3-6 mph. Within a couple hours things will have heated up significantly to the low 60s in Hopkinton. Meanwhile in Boston around the finish line near Copley Square things will be slightly cooler with temps in the low 50s and light west winds around 3-6 mph in the morning. As we get into the afternoon, towards the end of all of the events,temps look to max out in the mid to upper 60s. Dew points at both locations look to remain relatively low, so humidity will not be a factor for the runners. However, as runners get close to Boston in the afternoon, a sea breeze will be kicking in with winds between 5-10 mph.  All in all, it is going to be a beautiful day for a marathon. After the marathon things will cool down into the night where we will have some late night moderate rain that moves through along with increased winds around 6-12 mph with gusts around 15-20 mph.

This will be the fifth year that our group has provided on site weather data at the Boston Marathon for the BAA, but how will it stack up to the other years that we have worked it? Last year was the worst of the years as we had a mist that lingered throughout the day across all locations at the marathon that runners had to deal with as well as temperatures that barely made it to the upper 40s across all locations. Capture.

Here is a look at starting line temps over the past four years. This year looks to fall around the same area as the 2013 and 2014 years with temperatures starting in the mid to upper 40s. Both years saw relatively calm winds between 3-6 mph, but 2013 saw the winds from the east, meaning the runners would face a headwind and have a longer race time, while 2014 saw a tailwind. Even at this low of speed, there would still be some assistance during wind gusts. This year sees more like 2014’s conditions with a slight tailwind from the WNW.  The conditions for the start line seem to favor this year being similar to 2014 overall with a light tailwind, cool to moderate temperatures and little humidity.

Looking at the finish line, it looks like we will see similar conditions as the start line, until the afternoon. Morning temperatures start off in the mid to upper 40s and quickly rise into the low 60s.


This is yet again similar to 2014’s conditions. Temperatures then started off in the upper 40s and hit the upper 60s to low 70s by the afternoon. This is what runners can expect again this year thanks to mostly sunny skies. Humidity will remain low throughout the entire event, so that will allow runners to stay better hydrated, but warm temperatures in the late morning/early afternoon may still pose some issues to runners. As per the norm in Boston, a sea breeze will kick in during the afternoon bringing highs near the finish line down a bit into the mid 60s.

Looking over our data, this marathon is not going to break any extreme records, this will actually be normal for this time of the year’s standards! The warmest we have seen was back in 2012 where temps started off in the upper 60s for the morning and made it to the mid to upper 80s across all locations by the afternoon! That year required race officials to offer deferrals to runner’s who wished to race the next year instead due to the extremely warm weather and high humidity levels. Nothing this dangerous should affect the runners this year.

The marathon always brings surprises each year as to the weather. Some years we have seen snow showers and others we have seen blistering hot temperatures. This year looks to fall right in the middle, which is not a bad place to be seeing how our weather patterns have been over the past few weeks! Thank the Omega block to our west for this beautiful weather! Good luck to all the runners and enjoy the race!