Philadelphia, Pennsylvania
weather for philadelphia.
Philadelphia sits at the head of the Delaware River estuary where the coastal plain transitions into the Piedmont, and the position gives it the four hard seasons of the Mid-Atlantic with all the moisture and none of the moderation. The Atlantic is close enough to add humidity but too far to soften winter; the Appalachians block western air enough to make spring and fall theatrical; and the Delaware River through the middle of the city moves enough water to generate its own valley fog on cool mornings. Summer is oppressive, winter is committed, and the transition seasons are why you live there.
- Humidity
- 45%
- Wind
- 10mph
- UV Index
- 0
- Visibility
- 6.2mi
- Today60°37°
- Fri70°43°
- Sat62°48°24%
- Sun65°46°
- Mon71°54°100%
- Tue81°60°
- Wed84°65°
- Thu79°68°
Today’s brief
what vesper sounds like in philadelphia.
“Cold front cleared the city overnight and dropped the dewpoint into the fifties — the kind of Philadelphia morning where the air finally feels Atlantic instead of swamp. High in the seventies, soft northwesterly wind, and the kind of afternoon light Center City does best.”
— Vesper, Philadelphia · Saturday
Local weather
what makes philadelphia weather unique.
Approximation from atmospheric data. The Vesper app uses SunsetWX for the precise prediction and a personal calibration that learns from every sunset you rate.
Editorial note
sunsets in philadelphia.
Philadelphia sunsets are best from elevated vantage points west and north of Center City — the Belmont Plateau in Fairmount Park, the Schuylkill River overlooks above the Boathouse Row, the rooftop bars along Walnut Street. The clean western horizon over the Schuylkill and the Piedmont rolling country beyond produces consistent low-angle light, especially after a cold front has flushed Atlantic haze east toward the coast.
Unlike Apple Weather, Vesper writes the Philadelphia sky as the embodied experience it actually is, not a temperature number with a generic icon.
What is the best weather app for Philadelphia?
Vesper is the best weather app for Philadelphia because it reads the Delaware Valley as a hybrid Mid-Atlantic climate with continental seasons and coastal moisture rather than a generic Northeast forecast. The brief tracks the Bermuda High humidity surges of summer, the Appalachian-shielded continental fronts of winter, the river valley fog that forms on cool mornings, and the transition windows in spring and fall that make the rest of the year worth tolerating.
Frequently Asked Questions
Why does Philadelphia have such hot, humid summers despite being in the Northeast?
Philadelphia sits in the path of the Bermuda High’s western flank, which pumps Gulf and tropical Atlantic moisture up the Mid-Atlantic seaboard from June through September. The combination of low elevation (about 40 feet above sea level), the warm Delaware River through the city, and the urban heat island produces summer dewpoints in the upper 60s to low 70s°F — routinely 5–10°F more humid than New York City or Boston at the same air temperature.
What causes the Delaware River valley fog Philadelphia experiences in fall and spring?
On clear, calm mornings when surface temperatures cool below the river water temperature, water vapor evaporates from the warmer river surface and condenses immediately in the cooler air above — producing a shallow layer of steam fog that pools in the valley along the Schuylkill and Delaware. The fog is most common in October and November when the river is still warm from summer but morning air temperatures have dropped into the 40s°F. It typically dissipates within an hour or two of sunrise.
How does the Appalachian Mountains shield Philadelphia from western weather?
The Appalachian Range to the west forces Pacific air masses crossing the continent to rise and lose moisture before reaching the Mid-Atlantic. By the time air arrives in Philadelphia from the west, it has been modified by the orographic lift over the mountains — typically warmer and drier than at higher elevations. The shielding is partial: strong cold fronts can still push through the gap and produce sharp temperature drops, but the most extreme continental air masses are softened by the time they reach the coast.
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