Spotty, light rain early then dry Monday – CBS Boston

BOSTON (CBS) – For the first time in 124 years of history, the Boston Marathon will not be held in April. Until 1968, the marathon was held on April 19, Patriots Day. It was then moved to the third Monday in April and has remained there ever since. From a meteorologist’s point of view, that’s about ideal. October in Boston is accompanied by far fewer possible weather complications than April. I don’t have to tell any New Englander that April can be quite temperamental here.

Take a look at the history of the Boston Marathon:

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

And the last two Boston? We had a record 1.57 inches of rain in 2018 and 0.72 ″ of rain in 2019, along with nasty thunder and lightning.

Then there is the sea breeze in April, the water temperatures are freezing in the 40s. So any type of day with a relatively light wind and decent heating of the terrain and you could have a difference of 20 at 30 degrees along the Hopkinton to Boston road. Runners can literally experience two entirely different seasons along the 26 mile course.

In October, sea breezes are virtually non-existent with much warmer ocean temperatures. Earth’s extreme temperatures at either end are also less dramatic. For example, look at the recordings for October 11:

High record: 82
Record low: 32

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

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

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

As we have been following the forecast over the past few weeks, it was pretty clear that the likelihood of an “extreme” weather day was low. Conditions were generally mild, but far from record territory. We haven’t had any frost near Boston yet, we haven’t even fallen below 50 in Boston yet (and that’s almost a record for the most recent one). The tropics have also calmed down in recent weeks, currently there is no named system anywhere in the Atlantic basin.

Thinking back to summer and fall here in 2021, if I asked you what you think would be our biggest weather threat on Marathon Monday, I bet you would almost guess one thing: rain. And you would be right! Boston is currently more than a foot of water above average so far this year and we have just come out of the wettest July-August-September period on record, so naturally there would be some rain. in the forecast.

But alas, I come with good news! The latest indications are that any rain we might receive on Monday would be very light, patchy, and moving ahead of the marathon as well.

Let’s detail the details:

Over the past few days, we’ve observed an area of ​​low pressure to the south and determined how much it could impact the area over the holiday weekend. Although the weather was cool and cloudy, very little rain fell in parts of New England. Some towns and villages recorded a few hundredths of an inch, but it was above Nantucket where more regular showers allowed slightly higher amounts, closer to 0.25 “. However, the heaviest rain was just right. off the coast.

The possibility of a downpour or downpour is possible until Monday morning before this offshore system pulls away and takes the rain with it.

So for Monday itself, while Hopkinton may have clouds to start with early morning fog, Boylston Street may have a sun break by the end of the race. Even with a slight chance of showers at the start, most of the day should be dry. Temperatures will be mostly in the 60s. It may seem warmer for runners with sun breaks, and there may be some communities that are close to 70 degrees.

Hourly forecast Monday:

6:00 am: Hopkinton 55, Boston 59, mostly cloudy, NE wind 4-8mph
9 a.m .: Hopkinton 58, Boston 62, mostly cloudy, wind ENE 5-10mph
Noon: Temperatures 65-69, sunburn, E wind 5-10mph
3 p.m .: Temperatures 66-72, sunburn, E wind 5-10mph
6 p.m .: Temperatures 65-69, Pt. Sunny, wind E 4-8mph

Probably a little warmer than most runners would like, but it’s shaping up to be a great 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 good weather!

As always, I urge you to stay tuned for updated forecasts this weekend on WBZ-TV, CBSBoston.com and CBSN Boston.

Follow Terry on Twitter @TerryWBZ