Weather in Philadelphia: Climate, Seasons, and Average Monthly Temperature

Located in the northeastern United States, Philadelphia is a city that truly experiences the four seasons, with drastic differences in temperatures from summer to winter. Philadelphia is located in an area known as the Delaware Valley and is bordered by three rivers—the Delaware, the Schuylkill, and the Wissahickon—which all contribute to the city's high humidity, most noticeably in the warmer months.

Throughout the year, temperatures can vary considerably. It’s common for winter to be very cold with January through March hovering between 20 and 40 degrees F (-7 to 4 degrees C) with snow and ice storms occurring fairly regularly. In summer temperatures usually reach the high 80s to the high 90s F (31 to 37 degrees C).

Fast Climate Facts

• Hottest Month: July (avg. high 88 degrees F / 31.5 degrees C)
• Coldest Month: January (avg. high of 41 degrees F / 5 degrees C)
• Wettest Month: July (4.5 inches)
• Best Month for Swimming: August 
• Most Humid Month: August (avg. 70 percent humidity)

Summer in Philadelphia

Muggy, hot, and humid are three words that you will hear often when you’re in Philadelphia during the summer months. It can be tough to deal with the high humidity. In fact, from June through August, many Philadelphia-area residents flock to the nearby New Jersey shore to escape the heat. It also rains a lot in the summer and the city tends to get late afternoon thunderstorms with heavy downpours, especially in July. Be sure to bring an umbrella and carry it with you if the forecast calls for precipitation.

During the warmer months, many Philadelphia restaurants open their outdoor terraces and rooftop bars come alive. There are also a number of areas throughout the city where you can stroll around outside and enjoy the sunshine, such as Fairmount Park, Penn’s Landing and Spruce Street Harbor Park.

What to pack: Philadelphia is very casual, especially in summer, so plan to be as comfortable as possible, especially if you are walking around outdoors. In addition to the umbrella, you may want to bring a light jacket as most restaurants, museums, and businesses are air-conditioned so you actually may be a bit chilly indoors.

Average Temperatures by Month

• June: 74 degrees F / 23.3 degrees C
• July: 79 degrees F / 26.1 degrees C
• August: 77 degrees F / 25 degrees C

Fall in Philadelphia

In early September there’s a shift in temperature as the fall season brings a slight chill in the air. The leaves on the many trees around the city start changing colors and the temperature starts dropping. The air is usually noticeably less humid than the summer months, but the city still experiences several days of sudden heat (called “Indian Summer”) that usually occurs in mid-October.

It’s ideal to explore the city in the fall, as the temperature is mild and it rains much less than the summertime.

What to pack: Be sure to pack layers, a light jacket and perhaps include a medium-weight sweater or two (or perhaps a light scarf) in the mix.

Average Temperatures by Month

• September: 70 degrees F / 21 degrees C
• October: 58 degrees F / 14.4 degrees C
• November: 48 degrees F / 8.8 degrees C

Winter in Philadelphia

Philadelphia gets cold in the winter but brings a mix of sun and clouds, so even if the mercury drops and you need your heavy coat, there is still a chance of a sunny day. However, there are usually long stretches of grey, cloudy, windy days as well.

What to pack: Think warmth! Bring all your winter layers and don’t expect to be outside very much. It’s recommended to wear a hat, scarf, gloves, and low boots or warm shoes. If snow is in the forecast, definitely bring your snow boots.

Average Temperatures by Month

• December: 38 degrees F / 3.3 degrees C
• January: 34 degrees F / 1.1 degree C
• February: 35 degrees F / 1.6 degrees C

Spring in Philadelphia

Spring usually arrives slowly in Philadelphia and the city really doesn’t start to warm up until late April. In fact, the area is known to get heavy snowstorms in March. Although you will start to see flowers begin to bloom and buds start forming on the trees (adding some color to the barren landscape), locals treat spring like a milder winter… and expect lower temperatures for much of the season.

What to pack: Spring is changeable! Be sure to pack carefully for the springtime, as anything can happen. Keep an eye on the weather forecast as you get nearer to your visit because this season can bring an unexpected snowstorm as well as higher than normal temperatures. To be on the safe side, pack layers, a heavy jacket, and a hat. It’s always a good idea to bring a raincoat or umbrella and rain boots during this time of year.

Average Temperatures by Month

• March: 44 degrees F / 6.6 degrees C
• April: 54 degrees F / 12.2 degrees C
• May: 64 degrees F / 17.7 degrees C

Average Monthly Temperature, Rainfall, and Daylight Hours