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Heat Wave Could Continue Hitting Records In Boston Area As Dangerous Temperatures Rise

BOSTON (CBS) – Remember that heat wave to start the month of June? It really set the stage for what the rest of June became. So it should come as no surprise that more 90s, including our next heat wave, are here to end the month.

A subtropical high, known as a Bermuda high, will be anchored over the Atlantic for most of this week. The flow around high pressure will funnel in the heat and humidity on generally active southwesterly breeze.

Currently, 2021 is in second place for the all-time warmest month of June on record for Boston, sitting at 72.9°. As the next few days play out, it is virtually a lock that 2021 surpasses 1976 as the warmest June on record. Blue Hill Observatory in Milton is also on pace to notch its warmest June on record, and Providence, R.I. on pace to finish first or second.

(WBZ-TV graphic)

Boston was just shy of 90 degrees on Sunday with a high of 89, so Monday was the first day of the heat wave.

heat wave track monday
(WBZ-TV graphic)

You need to have three consecutive days of 90 degrees or higher for the stretch to be officially called a heat wave, and Boston hit 97 degrees on Monday, tying a record for the date.

2021 Records MultiDay
(WBZ-TV graphic)

But the highest temperatures are likely to occur on Tuesday. Record highs may again be challenged in Boston.

Forecast High Tuesdays
(WBZ-TV graphic)

We're expecting highs 94-99F across the area (away from the South Coast) and, along with sticky tropical dewpoints, heat indices will reach into the triple digits. Tuesday's heat indices may go as high as 102-108F.


Heat Advisories have been issued for nearly all of southern New England, except for the Cape and Islands. Plan to limit outdoor activities, seek shade or air conditioning, stay hydrated and take breaks if you work outside. Also, keep in mind the inside of the car is much hotter and can be extremely dangerous within minutes in heat like this. The heat wave will continue into Wednesday before a massive shift comes toward the end of the week. Scattered downpours and storms are likely Thursday while humidity stays high, but we may struggle to get out of the 60s in spots on Friday and Saturday!

Somewhat notably, multiple heat waves in a season that occur solely in the month of June (start/end date both in June) have only happened one time — 1941. It's likely to happen for 2021.

At the moment, there have been 9 days of 90°+ days for Boston for the season. This is well-ahead of our season-to-date average of two days. Boston will likely finish June with (9) 90F days during the month for the 2nd most 90s on record for June.

Looking ahead, it's looking like a very wet and cool start to the 4th of July holiday weekend. But there is some hope for the 4th itself. If this system can depart on time, we'll see a mixture of sun and clouds and temperatures in the 70s.

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