Excessive heat and humidity will resume this week statewide, as Boston prepares for its third heat wave this season.

Rain-free — but wretchedly humid — weather dominated the state today, according to the National Weather Service. Temperatures reached 90 degrees in Boston at about 11 a.m., but dipped into the high 80s this afternoon as a seacoast breeze developed.

Last year, Boston endured two heat waves, one in June and one in July, according to the weather service. Temperatures must hit at least 90 degrees for three straight days to qualify as an official heat wave.

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“A couple of days of a heat wave in summer are not unusual,” said meteorologist Bill Simpson. “But we are seeing these for a more prolonged time and more often.”

Skies will remain mostly sunny statewide today, with the coupling of high temperatures and dew points resulting in stifling afternoon temperatures that could feel like 100 degrees inland.

A heat advisory is in effect today until 8 p.m. this evening in Eastern Massachusetts and portions of the Connecticut River Valley in Massachusetts, with expanded heat advisories likely throughout the week.

Tonight will see mild temperatures in the 70s, and patchy fog throughout the state. A slight south wind could develop after midnight, with winds reaching six miles per hour.

Another heat advisory is likely Tuesday, with repeat conditions of Monday likely throughout much of the state. There is a twenty percent chance of precipitation for Tuesday.

Temperatures will again climb into the 90s on Tuesday, with dew points in the 70s. Skies will stay sunny and temperatures are likely to remain in the 90s through Friday, with a thirty percent chance of statewide showers and thunderstorms Thursday through Saturday.

Sunday will provide the only real respite from the heat and humidity this week, with a cold front likely to impact Massachusetts by early Sunday morning. This comfortable air mass will decrease humidity levels, according to the weather service. The high for Boston on Sunday is expected to be a comparatively chilly 81 degrees.