Question: when does the weather cool down in pennsylvania?
Answer: Weather in January January is generally the coldest month of the year in Pennsylvania as the temperatures plummet below 0°F (-17.8°C) in many places. The average low temperatures are in the frigid 12°F (-11.1°C) to 20°F (-6.7°C) zone, and the average high temperatures are in the 30°F (-1.1°C) to 40°F (4.4°C) range.