Greencastle (PA) Temperature by Month

Greencastle in Pennsylvania, United States of America sees significant seasonal temperature differences, with daytime highs between 4°C (39°F) in January and 31°C (88°F) in July, averaging 18°C (64°F) annually. Explore the full monthly breakdown below.

Visitors to Greencastle will encounter a climate influenced by big temperature differences across the year. Nighttime temperatures range from 19°C (66°F) in July to -5°C (23°F) in January.

The chart below illustrates the average maximum day and minimum night temperatures in Greencastle by month:

The coolest part of the day is typically between 4 AM and 6 AM, while 3 PM is usually the warmest, when solar heating is at its peak.

The chart below shows the average temperature throughout the year:

Greencastle's average annual maximum temperature is 18°C (64°F). To put that in context, here's how it compares to a few well-known destinations:

Rome, Italy averages 20°C (68°F) annually, with reliably warm summers and comfortable winters.

Interlaken, Switzerland averages 8°C (46°F) a year, with cold winters and cool summers thanks to its Alpine setting.

Chicago, USA averages 15°C (59°F) annually, known for extreme seasonal swings, from bitterly cold winters to warm summers.

Adelaide, Australia averages 21°C (70°F) a year, with warm summers, mild winters, and relatively low rainfall year-round.

Climate temperature data is typically calculated as a 30-year average. This smooths out year-to-year variability and gives a more reliable picture of what a place is actually like, rather than what happened in any single unusual year.

The readings come from a range of sources, land-based weather stations, ocean buoys, ships, and satellites. That data is collected by weather services around the world, then pooled, quality-checked, and averaged to produce the climate records you see here.

Whether a city sits on the coast or deep inland makes a significant difference to its climate. Coastal areas tend to have more stable temperatures year-round, large bodies of water absorb heat slowly in summer and release it gradually in winter, keeping extremes in check. Cities far from the sea don't benefit from that buffer, which is why continental climates tend to have hotter summers and colder winters than their coastal counterparts at the same latitude.

For more on Greencastle's weather, including monthly rainfall, sunshine hours, and humidity, visit our Greencastle climate page.