Final answer:
On December 21, the winter solstice, the North Pole experiences zero hours of sunlight due to the Earth's tilt, resulting in 24 hours of darkness.
Step-by-step explanation:
The North Pole receives zero hours of sunlight on December 21, which is the date of the winter solstice in the Northern Hemisphere. This phenomenon occurs because the North Pole is tilted away from the Sun, resulting in 24 hours of darkness. Conversely, the South Pole experiences continuous illumination or the midnight Sun, and the Sun reaches the zenith for observers on the Tropic of Capricorn. Regions within the Arctic Circle, including the North Pole, are engulfed in darkness during this time, which also marks the start of winter in the Northern Hemisphere.