Weather at the Boston Marathon 2021: forecast by meteorologist David Epstein

The weather forecast is always important to the Boston Marathon, and the time of year makes this race unique.

In April, race day temperatures can be cold or hot. But in October there is a little less opportunity for great heat or great cold – and that is the case this year.

Here is my full forecast for the 2021 Boston Marathon:

How warm will it be during the marathon?

At sunrise on Monday, temperatures in Hopkinton will be just under 60 degrees and will reach and even exceed this mark fairly quickly. Around 2 p.m. it should be almost 70 degrees and a bit muggy in the air.

Temperatures will be in the mid to high 60s for much of the race.

I expect a lot of cloud cover, but sometimes the sun can shine through, especially as we get deeper in the mornings and afternoons. Interestingly, the sun is 20 degrees lower at this time of year than in April. This factor dramatically reduces the chances of getting sunburn, which can often occur in the spring.

Will it rain on marathon Monday?

Depression will happen south of New England on Sunday night and early Monday, and the rain cover could move north enough to bring in a quick early morning shower. This is only a small possibility, and if it does happen the risk will be gone by mid-morning.

And what about wind?

Wind won’t play a big role during the race. Any headwind will be slight.

The mild weather will continue into the next week. Whether you’re visiting Boston or this is your home, enjoy the race.