The Philly region will be under a freeze watch this week
Philadelphia proper could see the mercury fall to 31 or 32 degrees, and outlying, more rural areas may go as low as the mid-20s.
If you have any plants that can be moved indoors, you may want to consider bringing them inside Tuesday night through Wednesday morning.
During that time, the Philadelphia area will be under a freeze watch, with temperatures expected to dip to or just below freezing, according to the National Weather Service. Philadelphia proper could see the mercury fall to 31 or 32 degrees, and outlying, more rural areas may go as low as the mid-20s, said Ray Martin, a meteorologist with the weather service’s Mount Holly office.
“It will be one of the colder mornings we’ve seen in April in a while,” Martin said. “But we aren’t expecting any records. This time of year, we can see temperatures in 20s or high teens, so it’s definitely one of the colder April mornings.”
If we do see freezing temperatures, it would still be somewhat unusual for this time of year.
In recent years, the final freeze date as measured at Philadelphia International Airport on average has come right around March 30, Martin said. So, should we see a freeze Tuesday into Wednesday, it would be about nine days later than we have become used to. The suburbs, meanwhile, often see final freezes around mid-April.
But that’s not typically the case in the city. Last year, for example, the last freeze came on March 9 — one of the earliest last freezes this century. The earliest last freeze in that period, meanwhile, came March 8, 2020.
Philadelphia’s most recent late last freeze, Martin said, came in 2022, when April 18 brought Philadelphia’s final frigid temperatures.
“It’s a bit late for the city, but not unprecedented,” Martin said.
Freezing temperatures Wednesday aren’t also entirely certain. In a Monday afternoon forecast, the weather service predicted a 50% to 60% chance of temperatures at or below freezing for the Delmarva region.
While the weather service typically doesn’t issue freeze warnings or watches for the Philadelphia metro area until April 11, the abnormally warm weather in recent weeks has led to trees and flowers blooming ahead of schedule. A late freeze could pose a threat to sensitive vegetation that has already started blooming, making the freeze watch issued on Monday prudent, Martin said.
If this week does bring a late freeze, it would likely happen between midnight Tuesday and 8 or 9 a.m. Wednesday, Martin said. The last time this year subfreezing temperatures were measured at Philadelphia International Airport was March 29, according to weather service data, when we hit 31 degrees — essentially right on time for regular expectations.
And if a freeze does come to pass, Martin said, it would be nothing compared to the previous record low for April 8, Wednesday’s date. That came in 2018, when the mercury dropped to a “bone-chilling” 23 degrees.
As of Monday afternoon, there were no further freeze threats on the horizon, though we could have another cold night Wednesday into Thursday morning. After that, lows are expected to bottom out in the low 50s later in the week.
“It could be a lot worse,” Martin said.