By Terry Eliasen, Meteorologist, WBZ-TV Exec. Weather Producer

BOSTON (CBS) – For the first time in its 124 year history, the Boston Marathon is not being run in April. Through 1968, the Marathon was run on April 19th, Patriot’s Day. It was then moved to the third Monday in April and has stayed there ever since. From a meteorologist’s perspective, this is just about ideal. October in Boston comes with much fewer possible weather complications than does April. I don’t have to tell any native New Englander that April can be quite fickle here.

Just take a peek at Boston Marathon history:

87 degrees on April 16, 2012
28 degrees on April 19, 1926

How about the last two Boston’s? We had a record 1.57 inches of rain in 2018 and 0.72″ of rain in 2019 along with some nasty thunder and lightning.

(WBZ-TV graphic)

Then there’s the sea breeze in April, the water temperatures are frigid, in the 40s. So, any type of day with relatively light wind and decent heating of the land and you could have a 20-to-30 degree difference along the route from Hopkinton to Boston. Runners can literally experience two entirely different seasons along the 26 mile route.

(WBZ-TV graphic)

In October, sea breezes are basically non-existent with much warmer ocean temperatures. The land-based temperature extremes on either end are also less dramatic. For instance, look at the records for October 11:

Record high: 82
Record low: 32

These are about 5-to-10 degrees less extreme than the typical marathon dates in April.

Essentially, in October, there really is very little concern of a severe weather day with one exception, tropical systems. We are just past the peak of our hurricane season in October and typically there is always something to watch in the Atlantic or Caribbean this time of year. Of course, the chances of a hit in Boston on any given day is very low.

And that brings us to our first October Boston Marathon here in 2021.

Let’s break down the details:

While Hopkinton may have clouds to start with some early morning fog Monday, Boylston Street might have a break of sun by the end of the race. Even with the slight chance of showers early on, most of the day should stay dry. Temperatures will mostly be in the 60s. It may feel warmer to runners with any breaks of sun, and there may be some communities that do get near 70 degrees.

(WBZ-TV graphic)

Hour-by-hour forecast Monday:

6 a.m: Hopkinton 55, Boston 59, mainly cloudy, wind NE 4-8mph
9 a.m: Hopkinton 58, Boston 62, mainly cloudy, wind ENE 5-10mph
Noon: Temperatures 65-69, breaks of sun, wind E 5-10mph
3 p.m: Temperatures 66-72, breaks of sun, wind E 5-10mph
6 p.m: Temperatures 65-69, Pt. Sunny, wind E 4-8mph

Probably a bit warmer than most runners would like, but looks like a terrific day for spectators!

If you are one of the thousands of runners this year, on behalf of the entire WBZ-TV Weather Team I wish you good luck and great weather!

Follow Terry on Twitter @TerryWBZ