The forecast for Wednesday evening shows clouds will increase and a 40 percent chance of showers and thunderstorms, but mainly after 1 a.m., according to the National Weather Service.
The odds of Long Island's drought conditions easing improve on Thursday, when a thunderstorm might strike after 7 a.m.
The chance of rain rises to 100 percent Thursday, and some storms even might bring heavy rain, the Upton-based forecasters said on their website. Long Island could see a half inch to three quarters of an inch of rain.
Showers might continue early Friday, which should be mostly cloudy, with a high of only 78.
That is much cooler than Wednesday, when the high was forecast at 87, just four degrees below Tuesday's record-breaking 91 degrees at MacArthur Airport in Ronkonkoma.
The normal high for Sept. 9 averages just 77 degrees.
Cool but sunny weather should prevail at the beginning of the weekend, with Saturday's temperatures rising to about 77, though there might be rain after 10 p.m., the weather service said.
Sunday will be mostly cloudy, with a 40 percent chance of rain, and a high of around 75.