The earliest sunset in December 2025 in Pennsylvania will be
around December 7th, with specific times varying by location, such as 4:51 PM in Williamsport and 4:47 PM
in Hatfield. This occurs a few weeks before the winter solstice on
December 21st, due to a phenomenon where the clock's effect of slowing
down the rate of sunset becomes greater than the geometric effect of the
earth's tilt. Reason: This happens just before the winter solstice because the "clock effect" of slowing down the sunset time outweighs the "geometric effect" of the Earth's tilt at this time.
The latest sunrise in December 2025 in Pennsylvania will be around
7:39 a.m. on December 20 and 21,
though this varies by location within the state. The latest sunrise of
the entire winter season will actually occur shortly after the winter
solstice, in early January. - Around December 20-21: Sunrise is approximately 7:39 a.m. in places like Pittsburgh, PA.
- Winter Solstice (around December 21): This is the shortest day of the year, but the sunrise time is not the absolute latest of the winter season.
- Early January: The latest sunrise of the winter occurs after the solstice, around January 5th in locations near the 40-degree north latitude line.
