From the National Weather Service:
Drink in the relief we got Thursday. The heat and humidity make a comeback this afternoon, and stay with us through the weekend. Here's the forecast high temps for today.
Today will be the easiest day of the three.
URGENT - WEATHER MESSAGE National Weather Service Boston/Norton MA 401 AM EDT Fri Jul 19 2019 MAZ022-023-191615- /O.CON.KBOX.HT.Y.0002.190719T1600Z-190722T0000Z/ Barnstable MA-Dukes MA- Including the cities of Chatham, Falmouth, Provincetown, and Vineyard Haven 401 AM EDT Fri Jul 19 2019 ...HEAT ADVISORY REMAINS IN EFFECT FROM NOON TODAY TO 8 PM EDT SUNDAY... * HEAT INDEX VALUES...In the 80s today, and 95 to 100 on Saturday and Sunday. This will be due to temperatures in the upper 80s and lower 90s, and dewpoints in the low to mid 70s. * TIMING...Noon Friday through Sunday evening, however the very worst of the heat will occur Saturday and Sunday. * TEMPERATURE...Actual air temperatures will be in the upper 80s Friday, increasing to the 90 to 95 degree range both Saturday and Sunday. It will not cool off much overnight, with lows in most areas only dropping to the mid 70s. * IMPACTS...The heat and humidity may cause heat stress during outdoor exertion or extended exposure. * LOCATION... Cape Cod and Marthas Vineyard. PRECAUTIONARY/PREPAREDNESS ACTIONS... A Heat Advisory means that a period of hot temperatures is expected. The combination of hot temperatures and high humidity will combine to create a situation in which heat illnesses are possible. Drink plenty of fluids, stay in an air-conditioned room, stay out of the sunshine, and check up on relatives and neighbors. Young children and pets should never be left unattended in vehicles under any circumstances. This is especially true during warm or hot weather when car interiors can reach lethal temperatures in a matter of minutes.