Final answer:
As you go farther north on December 21, the number of daily sunlight hours decreases, leading to longer nights the closer you get to the Arctic Circle, which experiences a 24-hour night on this date. The decreased daylight is due to the Earth's tilt and is the shortest in the Northern Hemisphere for the year, indicating the winter solstice.
Step-by-step explanation:
On December 21, which is the date of the winter solstice in the Northern Hemisphere, you will notice that the number of daily sunlight hours decreases as you travel farther north. At the Arctic Circle, there is a 24-hour night, meaning that the Sun does not rise at all. This contrasts with the situation at the Tropic of Capricorn, at latitude 23° S, where the Sun is directly overhead at noon.
In locations such as the United States and Southern Europe, the daylight hours might be only 9 or 10 hours. The reason for this variation in daylight is due to the Earth's tilt, which causes different parts of the planet to receive varying amounts of sunlight over the course of the year.
The length of daylight on this solstice is the shortest of the year in the Northern Hemisphere, leading to longer nights and thus contributing to the colder weather. As one moves towards the polar regions, this imbalance between day and night accentuates, culminating in a full 24 hours of darkness at the North Pole itself, a phenomenon known as the polar night. Conversely, December 21 marks the beginning of summer in the Southern Hemisphere with longer days and the occurrence of the midnight Sun in the Antarctic Circle.