Sunday promises to be a sun-splashed summer day across Long Island before the workweek begins and brings with it threats of rain, forecasters said.

"Today's going to be a perfect summer day with low humidity, plenty of sunshine and nice and warm," said Carlie Buccola, a meteorologist with the National Weather Service at Upton. "Temperatures will be slightly above average."

Highs Sunday will reach the mid-80s. Buccola said the average for Islip this time of year is 82 degrees. Lows Sunday will be in the upper 60s near 70.

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Monday, look for highs in the mid-80s again but there will be the first chance of a showers or thunderstorms for the week. There will be a 20 percent chance of precipitation an night when lows will be in the lower 70s.

Tuesday and Wednesday will be dry, with a mostly sunny day predicted for Tuesday when highs will be in the mid to upper 80s and temperatures dip at night to the upper 60s.

"There'll be increasing humidity Monday and Tuesday," Buccola said.

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Look for another sunny day on Wednesday with highs in the low to mid-80s. But at night, a 20 percent chance of a showers returns and lows will be in the mid-60s.

Highs Thursday will be in the low 80s. There will be a mix of sun and clouds and a 30-percent chance of showers and thunderstorms during the day and a 25-to 30-percent chance of rain at night when temperatures will be in the mid-60s.

A pretty good start to the weekend comes in the form of a partly sunny day Friday with highs in the low 80s. There's a slight chance of a shower of thunderstorms again and lows will be in the mid- to upper 60s.

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"Its definitely not that out of the ordinary for temperatures this time of year," said John Isgro, a News 12 Long Island meteorologist. "There's just a system that's going to be hanging around the coast that'll bring us unsettled weather. "