Weather forecasters warn that a week with temperatures bouncing up and down will begin with the season's first freeze Sunday night.
Temperatures will drop into the 30s across Long Island and into the high 20s in eastern Suffolk Sunday night. But there is relief in sight by midweek and then another warming up once the weekend comes around.
"We're going to see our first freeze, which is typically due around this time of year," said David Stark, a meteorologist with the National Weather Service in Upton. "These temperatures are going to effectively end the growing season. That's when any sensitive plants, crops or vegetation could be killed off if they're not properly treated or covered."
The freeze warning is in effect until 9 a.m. Monday.
On Monday, the skies should be sunny but temperatures cold, about 10 degrees below normal, Stark said, adding that the high reading should be in the upper 40s where it would normally be in the 50s. The nighttime temperatures will dip down into the 30s.
"Monday night is likely still to be very chilly but we're not expecting another freeze, likely just above freezing," Stark said.
Tuesday begins a mild warm-up, Stark said, with daytime temperatures reaching the low 50s under partly sunny skies and nighttime readings staying above 40 degrees. But the weather jumps into the sunny low 60s by Wednesday because of a Canadian high-pressure system, he said, adding that the nighttime low will be around 51 degrees.
"There's going to be an up and down pattern," Stark said. "The week is starting on the cool side and then it warms up a little bit."
Showers are possible Thursday, Stark said, but temperatures could reach 64 degrees. By nightfall, the chance of showers is 70 percent.
Friday is expected to be sunny with a daytime high of around 52 degrees, with the nighttime low dropping to 36 degrees under clear skies.
By Saturday, it warms up again, as the daytime temperature could reach 55 degrees.