The forecast calls for the lowest temperatures of the season over the weekend, as the region falls under a steadily increasing chill.
The Code Blue in effect since Dec. 28 is likely to continue at least through the weekend, according to the city. Outreach teams drive around, assisting the homeless and urging them to go to shelters. To get help for someone out in the cold, call 215-232-1984.
Today's high will be around freezing in Philadelphia, with gusts of up to 30 m.p.h., making it even feel even colder. Tuesday through Thursday might creep into the mid 30s, but overnight lows should be in the low 20s.
Snow is also a possibility Thursday night into Friday.
Then Friday and Saturday should bring lows in the mid teens, edging this winter's previous coldest mark, 17 on Dec. 23.
Saturday's predicted low of 15 is about 10 degrees below early January's normal lows.
The suburbs are likely to be a couple of degrees colder.
That's not historically frigid, though.
Last winter, a half-dozen days hit 15, and three were even colder, reaching 10 on Jan. 16, 6 the following night, and 13 on March 3.
January's record lows are all in the single digits - and a dozen of those were below zero, including minus-7s on Jan. 17, 1982, and Jan. 22, 1984.
Most of those subzero records were set in the latter half of January - the coldest part of the year in the Philadelphia area.
The region's all-time low, however, was minus-11, set on Feb. 9, 1934.
For more on the forecast go to http://www.philly.com/weather. Enter a zip code or town name to change the location of the forecast.
Contact staff writer Peter Mucha at 215-854-4342 or firstname.lastname@example.org.