BOSTON (CBS) – For the first time in its 124 -year history, the Boston Marathon will not run in April. By 1968, the Marathon was run on April 19, Patriot Day. It then moved to the third Monday of April and has remained there ever since. From a meteorologist’s perspective, this is just about perfect. October in Boston has fewer possible weather complications than April. I don’t have to tell any native New Englander that April can be volatile here.
Just a peek at the history of the Boston Marathon:
87 degrees on April 16, 2012
28 degrees on April 19, 1926
How were the last two Boston? We recorded 1.57 inches of rain in 2018 and 0.72 ″ of rain in 2019 along with some bad thunder and lightning.
Then there is a sea breeze in April, the water temperature is cold, at about 40. So, any kind of sun with gentle winds and decent ground heating and you can have 20-to-30 degrees route difference from Hopkinton to Boston. Runners can literally experience two completely different seasons along the 26 mile route.
In October, sea breezes are usually absent with warmer ocean temperatures. The ground-based temperature in excess at either end is less noticeable. For example, see the records for October 11:
High record: 82
Low record: 32
This is about 5-to-10 degrees lower than the usual marathon dates in April.
Importantly, in October, there is really very little concern of an extreme weather day with one exception, tropical systems. We just passed the peak of our hurricane season in October and usually always have something to watch in the Atlantic or Caribbean at this time of year. Of course, the chances of hitting Boston on any given day are very low.
And it will take us to our first October Boston Marathon here in 2021.
As we’ve been tracking the forecast over the past few weeks, it’s pretty clear that the likelihood of an “extreme” weather day is low. Conditions have been generally mild, but nowhere near record territory. We haven’t had frost anywhere near Boston yet, which is why we haven’t fallen below 50 in Boston (and that’s close to a record for the latest season). The Tropics have also calmed down in recent weeks, with currently unnamed systems anywhere in the Atlantic basin.
Thinking of summer and falling here in 2021, if I ask you what you guess will be the biggest threat during the Marathon Monday I bet almost all of you guess one thing-rain. And you will be right! Boston is currently more than a foot of water above average so far this year and we just came out with the most recent July-August-September stretch recorded, so naturally there will be rain in the estimated.
But alas, I came with good news! The latest indications are that any rain we may receive on Sunday and Monday will be very light, spotted and also moving before the Marathon.
Let’s delete the details:
A ridge of high pressure begins to lose grip on the region, as an area of low pressure well to the south slowly moves towards the north. The likelihood of rain will increase on Sunday, but most of the heavy rain will remain on the shore. Expect mainly cloudy conditions with temperatures in the 60s.
The morning should be dry, but some showers may develop by noon and in the afternoon. The highest risk is in the entire southern part of the state, but even in the Boston area, a shower or two cannot be denied. The opportunity to bathe is possible by early Monday before this shore system pulls in and carries the rain with it.
So for Monday itself, while Hopkinton may be stuck in the clouds to start some early morning, Boylston Street may have a day to finish the race. Although there is a slight chance of early rain, most of the day should remain dry. Temperatures are around 60.
Hour-by-hour forecast Monday:
6 am: Hopkinton 55, Boston 60, mainly cloudy, winds NE 4-8mph
9 am: Hopkinton 60, Boston 65, mainly cloudy, winds ENE 5-10mph
Noon: Temperature 68-72, days breaking sun, wind E 5-10mph
3 pm: Temperatures are low to mid 70s, sun break, wind E 5-10mph
6 pm: Temperature 65-69, Pt. Sunny, wind E 4-8mph
It was probably a bit hotter than most runners would like, but it looked like a horrible day for the spectators!
If you are one of the thousands running this year, on behalf of the entire WBZ-TV Weather Team I wish you good luck and great weather!
As always, I urge you to stay up to date with updated weekend forecasts on WBZ-TV, CBSBoston.com and CBSN Boston.
Follow Terry on Twitter @TerryWBZ