Sunday morning starts with some fog and temperatures in the 50s and 60s. It will be cloudy during the morning, but most places will be dry. It will turn more humid over the course of the day, however.
More scattered showers, downpours, and thunderstorms will develop during the afternoon. That will happen first in Western and Northern New England around lunchtime, before arriving closer to Boston late in the afternoon and during the evening. Highs will reach the 70s to near 80 as that happens.
Humidity drops, as do temperatures, heading into Monday. With a mix of sun and clouds highs will be in the 60s and 70s. There still may be a spot shower or storm, but many will stay dry.
Tuesday looks beautiful, with lots of sunshine thanks to high pressure overhead. Highs will be in the 70s to near 80. Humidity bumps back up mid to late week, and temperatures return to the 80s.
A front will bring scattered showers and storms late Wednesday into Thursday. Although early still, next weekend into the week of July 4 look to feature warmer than average conditions.