Here’s Dave Epstein’s Marathon Monday weather forecast

Conditions will be excellent for spectators and quite good for runners, although it will become a bit warm in the late morning into the afternoon.

In this April 17, 2017 file photo, runners in the 121st Boston Marathon. AP Photo/Charles Krupa, File

After a couple of year’s hiatus on Patriots Day due to COVID, the Boston Marathon will run again on the April 18 holiday. The weather can vary widely for the runners, ranging from cold and wet to hot and humid. This year’s conditions will be excellent for spectators and quite good for runners, although it will become a bit warm in the late morning into the afternoon.

When runners are gathering before the start of the race, temperatures will be a bit chilly– in the lower 40s. I suspect that runners will need to keep warm with some extra layers, which will quickly become giveaways on the way to Boston.

Temperatures will be in the 40s on Monday morning as runners are gathering for the race. – WeatherBELL

The map above shows temperatures at 8 a.m. Notice there’s not much of a difference between the suburbs and Boston, and this will be the case for most of the day. Later on in the morning temperatures will rise into the 50s. It will still be dry. The map below shows temperatures around 11 a.m.

By 11 a.m. Monday, readings will have warmed about 10 degrees from their lows. – WeatherBELL

Finally, by early afternoon readings will be up near 60 degrees, which is great for spectators, but a bit warm for some runners, although the elite athletes will have finished by then.

Early afternoon features temperatures near 60 degrees in eastern New England. – WeatherBELL

Winds will be coming from the west early in the race as indicated on the map below. Notice the arrows are pointed from the west towards the east, which we call a westerly wind.

Winds will be light from the west on Monday, turning more southerly later in the day. – WeatherBELL

In terms of sky conditions, I’m expecting nearly cloudless skies to start the race with some increase in cloudiness later on in the afternoon. There’s no chance for any precipitation. 

The percentage of clouds on Monday will be very low through early afternoon. – WeatherBELL


Since the Marathon date moves around a bit, I decided just to look at April 18 weather in the past. We have been as warm as 94 degrees back in 1896, but as warm is 93 in 1976, which was a Sunday and followed by a very hot Marathon Monday.

April can bring everything from readings in the 20s to highs in the 90s. – NOAA

Daily Local Weather Forecast

  • Today May 26
    Intermittent clouds
    Intermittent clouds
    68° 60°
  • Fri May 27
    Mostly cloudy
    Mostly cloudy
    78° 65°
  • Sat May 28
    73° 60°
  • Sun May 29
    Intermittent clouds
    Intermittent clouds
    70° 57°
  • Mon May 30
    Intermittent clouds
    Intermittent clouds
    75° 60°
  • Tue May 31
    Mostly cloudy
    Mostly cloudy
    71° 59°
  • Wed June 01
    Partly sunny
    Partly sunny
    75° 61°


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