This March is the warmest on record at the National Weather Service's recording station in Islip, said Joe Pollina, meteorologist with the service's Upton office.
The average temperature was 47.3 degrees, breaking the previous record of 45.1 degrees that was set in 2010, he said.
The National Weather Service began keeping records at the Islip station in 1986.
The warming trend continues for April, with a damp start to the month turning into dry, warmer days later this week.
There was a 70 to 80 percent chance of rain Sunday night into Monday, he said. Temperatures overnight were expected to be in the upper 30s to about 40.
Monday's highs will be in the middle 50s, beginning a warming trend that will last until Thursday, Pollina said. Monday night's lows will be in the 30s.
Come Tuesday, expect highs in the upper 50s to around 60 degrees, with lows in the lower 40s and a chance of precipitation overnight thanks to a weak low-pressure system expected to move through the area, Pollina said.