Final answer:
In the Northern Hemisphere during winter, shadows point north because the Sun is positioned to the south when at its highest point. This occurs around the winter solstice on December 21st, when the North Pole is tilted away from the Sun.
Step-by-step explanation:
In the winter solstice, which occurs around December 21st in the Northern Hemisphere, shadows point towards the north. This happens because the Sun is low in the sky, as the North Pole is tilted away from the Sun during this time. At noon, when the Sun is at its highest point in the sky (yet still low compared to other seasons), the shadows will point north because the Sun is south in the sky.
The duration of daylight is also shortest during this season, providing only about 9 to 10 hours of sunshine in the United States and Southern Europe. Overall, the shadow orientation helps us understand the Earth's tilt and seasonal changes.