Upper Darby, Pennsylvania

Climate of Upper Darby, Pennsylvania

North America

Upper Darby, Pennsylvania, is a township located in Delaware County, just west of the city of Philadelphia. Nestled in the southeastern part of the state, Upper Darby is part of the greater Philadelphia metropolitan area. Understanding the weather and climate of this region requires exploring its geographical location, topography, and the atmospheric conditions that shape its climate. See citiesplustowns for a full list of cities in Pennsylvania.

Geographic Location:

Upper Darby is situated in the southeastern corner of Pennsylvania, approximately 7 miles west of Philadelphia. It is part of the Delaware Valley region, an area characterized by its proximity to the Delaware River. The township is part of the greater Philadelphia metropolitan area, contributing to its diverse urban and suburban landscape.


The topography of Upper Darby is relatively flat, typical of the coastal plain region in southeastern Pennsylvania. The area does not have significant elevation changes or prominent geographical features. The landscape is characterized by suburban neighborhoods, parks, and commercial areas.

Climate Classification:

Upper Darby experiences a humid subtropical climate according to the Köppen climate classification. This climate classification is characterized by hot and humid summers, mild to cool winters, and a moderate amount of precipitation throughout the year. The specific subtype is often denoted as Cfa, where “C” represents a warm temperate climate, “f” indicates a fully humid climate, and “a” stands for hot summers.

Seasonal Variations:

  1. Summer (June-August): Summers in Upper Darby are warm and humid. Daytime temperatures typically range from the mid-80s to low 90s°F (29-35°C). Humidity levels can be noticeable, especially during heatwaves. Thunderstorms are common in the summer months, providing relief from the heat. The evenings generally cool down, offering some respite from the daytime warmth.
  2. Autumn (September-November): Autumn brings a gradual cooling of temperatures, with crisp and comfortable weather. Daytime highs range from the 60s to 70s°F (15-26°C), while nighttime temperatures can drop into the 40s°F (4-9°C). Fall foliage is a notable feature, with the changing colors of deciduous trees adding vibrant hues to the landscape.
  3. Winter (December-February): Winters in Upper Darby are characterized by cool temperatures and occasional snowfall. Daytime highs typically range from the 30s to 40s°F (1-9°C), and nighttime lows can dip into the 20s°F (-6 to -1°C). While snow is a regular occurrence, it is generally moderate in amount, and the township experiences a mix of snowy and rainy days. Winter weather systems are often influenced by the proximity of the Atlantic Ocean.
  4. Spring (March-May): Spring marks a gradual warming of temperatures and the return of blooming vegetation. Daytime highs range from the 50s to 60s°F (10-21°C), with an increase in daylight hours. Spring is characterized by variable weather, including occasional rain showers. It’s a time of renewal, with trees and flowers coming back to life after the winter months.


Upper Darby receives a moderate amount of precipitation throughout the year, with an annual average of around 44 inches (1,118 mm). Precipitation is relatively evenly distributed across the seasons, with slightly higher amounts during the summer months due to the prevalence of thunderstorms. Rainfall is essential for sustaining the region’s vegetation and supporting various ecosystems.

Wind Patterns:

The wind patterns in Upper Darby are influenced by its location in the northeastern United States and its proximity to the Atlantic Ocean. While not subject to extreme wind events, the township may experience breezy conditions, especially during storms and weather systems passing through the region.

Special Considerations:

  1. Urban and Suburban Dynamics: Upper Darby’s climate is shaped not only by natural factors but also by its urban and suburban landscape. The presence of buildings, roads, and other infrastructure can contribute to the urban heat island effect, where urban areas experience higher temperatures compared to surrounding rural areas.
  2. Proximity to Philadelphia: The close proximity to Philadelphia has cultural and economic implications for Upper Darby. The township benefits from the amenities and opportunities provided by a major urban center, and residents often commute to Philadelphia for work and recreation.
  3. Community Resilience: Given its location in the northeastern United States, Upper Darby is susceptible to weather events such as winter storms, heavy rainfall, and occasional heatwaves. The community’s resilience and preparedness for these weather events play a crucial role in mitigating their impact on daily life.

Upper Darby, Pennsylvania, experiences a humid subtropical climate with distinct seasons, influenced by its geographical location in the northeastern United States. The township’s weather is characterized by warm and humid summers, mild autumns, cool winters with occasional snowfall, and variable spring weather. The proximity to Philadelphia, combined with its suburban landscape, makes Upper Darby a unique part of the greater Philadelphia metropolitan area, where the climate reflects a balance between urban influences and natural elements.

Upper Darby, Pennsylvania