During which solstice does the Earth receive the least insulation?

The correct answer is the Winter Solstice, where the Earth experiences the least insolation. Insolation, or incoming solar radiation, is lowest during this time because the North Pole is tilted farthest away from the sun. This occurs around December 21-22 in the Northern Hemisphere. At this point, sunlight strikes the Earth at a significantly oblique angle, spreading the energy over a larger surface area and causing less intensity. Additionally, days are shortest during the winter solstice, contributing to the reduced amount of solar energy received.

In comparison, during the Summer Solstice, the Northern Hemisphere is tilted towards the sun, resulting in maximum insolation and longer daylight hours. The Spring and Autumnal Solstices occur when the tilt of the Earth is such that both hemispheres receive relatively equal amounts of sunlight, but neither experience the extreme low of insolation seen in winter.