Is Pennsylvania Humid Or Dry?

Wireless thermometer showing temperature, humidity, and wind speed

Pennsylvania is nestled in the northeastern region of the United States. It’s known for its beautiful landscapes, rich history, and cultural diversity. One question frequently asked is about the climate of Pennsylvania; is it humid or dry?

In this post, we’ll explore this topic and provide an overview of the weather in the Keystone State to help answer this question.

Humidity in Pennsylvania

Humidity is a common factor when discussing the state’s climate. It is a measure of the amount of moisture present in the air, meaning the more water vapor in the air, the higher the humidity.

Pennsylvania is large with a varying geography, so the humidity levels can differ significantly depending on where you are. Generally, the eastern part, where cities such as Philadelphia are located, tends to have higher levels due to its proximity to the Atlantic Ocean. In contrast, the western regions, including the Allegheny Mountains, tend to be less muggy.

So when visiting the Keystone State, different regions can offer a vastly different experience of the state’s climate depending on the season and time of year.

The variance in humidity levels across Pennsylvania is mainly due to the unique weather patterns. Specifically, the eastern part of the state is heavily influenced by the Atlantic Ocean, which tends to bring in moist air from the sea. When combined with warm temperatures in the summer, this can lead to high levels of moisture that can feel quite oppressive.

On average, the levels in this region can range from 70% to 90%, which is notably higher than the rest of the state. However, it’s worth noting that the levels can also vary on a day-to-day basis depending on weather conditions, so residents and visitors alike should prepare accordingly. Those sensitive to sweltering weather may want to plan their visits to the eastern part of the state during the year’s cooler months.

High overlook of forested mountains

In contrast to the eastern part, the Appalachian Mountains influence the western region of Pennsylvania. This mountain range can serve as a barrier and block the flow of moist air from the east, resulting in a drier climate than the eastern counterpart.

However, that does not mean that the western region is devoid of muggy weather. On average, levels can range between 40% to 60%, which is still moderately high. Therefore, visitors exploring the western part of the state can expect a somewhat drier and more temperate environment, which can be a welcome relief.

One important factor to consider when discussing the climate in Pennsylvania is the seasonal changes. The state experiences four distinct seasons, and this variation can significantly impact the humidity levels across the state.

Generally, in the summer months, the eastern region can become extremely humid due to the warm temperatures and proximity to the Atlantic Ocean. Conversely, levels tend to drop considerably during winter due to colder temperatures.

Keystone Answers Fun Fact: The maximum temperature record for the Keystone State was 111 °F on July 9 & 10, 1936, in Phoenixville, located in Chester County.

It’s worth noting that these seasonal patterns are not unique to Pennsylvania and are typical of a continental climate, which experiences fluctuations in temperature and moisture throughout the year. Visitors planning to travel to the state should keep in mind these seasonal changes when packing and planning activities.

Similar to the eastern region, the western part of the state also experiences seasonal shifts in moisture levels. During summer, visitors can expect lower humidity levels with a relatively dryer climate perfect for outdoor activities. However, in the winter, snow accumulation can contribute to increased levels in the area.

This increase is because snow is a source of moisture and can lead to higher moisture levels in the air as it melts. So overall, while the western region tends to be drier than the east, the seasonal changes can still significantly impact how humid or dry the area feels.

March snowfall in northern Pennsylvania

Pennsylvania’s climate is complex and varied, with humidity levels that change depending on multiple environmental factors. While the eastern part of the state typically experiences higher levels than the western region, the climate across the state can fluctuate considerably based on the season.

So back to the question, is Pennsylvania humid or dry? Pennsylvania’s climate is both humid and dry, depending on the region and season you’re in. The state’s eastern portion tends to be more humid due to its proximity to the Atlantic Ocean, while the west is drier because of the Appalachian Mountains.

Babbling creek with tall grass on each side

What is the Temperature Range in Pennsylvania

In general, Pennsylvania experiences a continental climate with four distinct seasons. Summer can be warm and humid, with temperatures averaging in the mid-to-high 80s (about 29-32°C) during the day and cooling off at night. Conversely, winters can be cold, with temperatures typically ranging between 20 and 40 (-6 to 4°C) during the day and dropping well below freezing (32°F or 0°C) at night.

Spring and fall tend to be mild, with temperatures ranging from the mid-50 to the mid-70s (about 12-24°C). However, it’s important to note that temperature ranges can vary depending on the region, with areas at higher elevations being considerably cooler than those closer to sea level.

Soggy or Not

In conclusion, Pennsylvania’s climate ranges from humid to drier depending on the region and season. The east is generally more humid due to its proximity to the Atlantic Ocean, while the west is drier due to the Appalachian Mountains.

The state’s varied climate and geography offer ample opportunities for visitors to explore, no matter what temperature or humidity levels they prefer. Be sure to check the weather forecast before your visit to ensure you’re adequately prepared for whatever Pennsylvania’s climate has in store.

Photo of author


I was born and raised in Pennsylvania; I love to travel, visit new destinations, explore unique locations, and meet great new people. However, sometimes, you don't need to travel far from home to find new adventures, so I decided now was the time to learn more about this great state I call home.