A Severe Thunderstorm Watch is in effect for all of Fairfield County until 8 p.m.
The threat of rain is expected to last until midnight, followed by most cloudy skies but with temperatures remaining in the high 70s overnight.
The summer heat wave that has gripped Fairfield County since late last week is expected to continue until at least Thursday. Temperatures should stay at or above 90 degrees before moderating slightly on Friday.
The National Weather Service said Monday's heat index could soar to as high as 96. A heat advisory remains in effect until 8 p.m. Monday.
It also said new rainfall amounts could be between a tenth and quarter of an inch, except higher amounts are possible in thunderstorms.
Click here to follow Daily Voice Norwalk and receive free news updates.