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First frosts of the year are reported in the Philly suburbs, with more possible on the weekend

The sun hasn't risen this late since Jan. 23. And don't miss that full moon Wednesday night.

Frost as it appeared in outside the weather service office in Mount Holly on this date two years ago. Scattered frost was reported Tuesday morning in parts of the Philly region.
Frost as it appeared in outside the weather service office in Mount Holly on this date two years ago. Scattered frost was reported Tuesday morning in parts of the Philly region.Read moreNational Weather Service

On a morning when the sun rose later than it has since late January, the region on Tuesday logged its first reports of scattered frost, and encores are possible on the weekend into early next week.

Temperatures dropped into the 30s in areas outside the city, and while they remained well above freezing, some surfaces were cool enough to whiten the dew, according to various social media reports.

And conditions overnight — clear skies and light winds under a cold moon — would argue for their validity, said Jonathan O’Brien, a meteorologist at the National Weather Service Office in Mount Holly.

But while readings fell to 38 degrees in Pottstown and 39 in Mount Holly, they didn’t get below 46 at Philadelphia International Airport.

» READ MORE: Philly winter forecasts call for early snow, a cold December, and a 100% chance of uncertainty

While that would have something to do with urban-heating influences, O’Brien said winds likely were factors. In Pottstown and Mount Holly the winds were nearly calm overnight, but they were blowing 10 to 13 mph at the airport. Daytime heat radiates into space more efficiently when skies are clear and winds are calm.

Still, although it was a paltry 2 degrees below normal, it was the lowest official Philadelphia reading of a very warm month in which temperatures have been better than 6 degrees above average, and the lowest since May 12.

After a few more days of a return to September-like conditions, a chill is due to return on the weekend, with overnight lows similar to Tuesday morning, O’Brien said. Daytime highs Monday aren’t expected to make it out of the 50s.

» READ MORE: First frost and freezing temperatures invade Philly region; 'heat island’ spares city

It’s that time of year, with the nights now outlasting the days by close to an hour.

On the bright side, that’s all the more darkness to enjoy the moon — Hunter, Dying Grass, Sanguine, or Blood Moon, whatever your pleasure — which will become full on Wednesday. With trees finally shedding some leaves, that should create more openings for moonlight.

Conveniently, the moon will rise right shortly after sunset Wednesday and set Thursday morning right before the run rises at 7:16:35 EDT, the latest it will have come up since Jan. 19.

And if you’re a glutton for moons, Jupiter will be quite visible in the night sky, and NASA says that with a telescope you should be able to sight its four bright moons, Ganymede, Callisto, Europa, and Io. Jupiter has 75 others.