Massachusetts is bracing for a sudden blast of intense summer heat that could trigger the first official heat wave of the season starting Monday, June 23. But before that, a short-lived yet potent heat surge will sweep through the region this Thursday, setting the stage for what looks like a stretch of scorching days next week.
Hazy heat and severe storms possible Thursday
This Thursday, June 19, temperatures are forecast to spike to 92°F (33°C), accompanied by a brisk southwest wind gusting up to 21 mph. The National Weather Service is warning of increased humidity and the possibility of late-day thunderstorms, which may bring thunder, lightning, and localized downpours.
The air quality is expected to deteriorate, with haze and heat combining to create potentially dangerous conditions for sensitive groups, particularly during the late afternoon and early evening hours.
Brief relief Friday and Saturday with dry skies
Friday, June 20, and Saturday, June 21, promise to be milder and drier, with sunny skies and more seasonable highs around 83°F (28°C). There’s a growing possibility that Saturday could mark the first rain-free Saturday in Greater Boston in over three months, a welcome break for those planning outdoor events.
Only a slight chance of rain is forecast late Saturday night, making the daytime hours ideal under bright June sunshine.
Sunday calm before an extended heat wave
Sunday, June 22, continues the tranquil pattern, with another pleasant and dry day, which will act as a calm lead-in to the intensifying heat dome expected to settle over Massachusetts starting Monday.
Heat wave begins Monday with highs near 94°F
From Monday, June 23, through at least Wednesday, daily highs are projected to reach 94°F (34°C) or higher, bringing dangerous heat levels and oppressive humidity to most of the state. This would qualify as the first heat wave of 2025, defined as three or more consecutive days with highs of 90°F (32°C) or above.
Long-range forecasts indicate that the intense conditions may break by Thursday, June 26, although the forecast remains uncertain. The heat will likely pose risks to public health, especially in urban areas like Boston, Worcester, and Springfield, where heat island effects may amplify the daytime and overnight temperatures.
