If it feels like the coldest time of the winter, well, that's because it is.
Though Thursday's frigid temperature fell short of a record, this week -- the third in January -- historically is Long Island's coldest stretch of winter, said Tim Morrin, a meteorologist with the National Weather Service in Upton.
"Between Jan. 22 and Jan. 26 is the time when we get the coldest weather of the season, so we're right there," Morrin said.
Winds made it feel even colder and this week's most extreme wind chill was recorded about 7 a.m. Thursday -- minus 12 at Gabreski Airport in Westhampton Beach, data show.
Daily lows since Monday have ranged from single digits to the low 20s at Islip, making this the coldest stretch so far of winter, the weather service said.
Thursday's low was 5 degrees in the early morning hours at Islip -- it was 15 degrees below the temperature typical for Jan. 24 but just missed Islip's record low of 4 degrees set in 2011.
The Long Island record for the coldest Jan. 24 is minus 1.5 degrees in 1978 at Brookhaven National Laboratory.
The freezing conditions contributed to the cracking of a train rail east of Mineola, problems that caused evening rush hour delays.
Friday, the high will be 25, but the forecast also calls for 1 to 2 inches of snow, from 4 p.m. to 1 a.m. Saturday.
Morrin said the temperatures mark the coldest in the area in the past two years. "These numbers we're seeing are very impressive," he said.
The cold has been good news for Riverhead Town's recreation department, which has been waiting for a year to open its new ice rink in Stotzky Park.
For those who prefer warmer weather, temperatures are expected to climb, beginning Monday.
The weather service said Monday's temperature is expected to push into the 30s, by Tuesday it should reach the 40s and then hit the 50s on Wednesday.
With John Valenti, Mitchell Freedman and Ellen Yan