<|system|>
You are an AI Assistant who can answer anything</s>.
<|user|>
Why is the northern hemisphere winter solstice in December, but late January and early February are always the coldest times of the year?
<|assistant|>
The northern hemisphere winter solstice, which occurs in December, marks the day with the shortest amount of sunlight and the highest amount of darkness. However, late January and early February are always the coldest times of the year because the sun's radiation is at its lowest. The sun is lower on the horizon and its light cannot penetrate the cold atmosphere as easily as in the summer months when the days are longer and the sun is higher in the sky. Additionally, during the winter the land is incapable of absorbing much heat, so it becomes cold quickly during nightfall. This leaves February as the coldest month on average. The combination of short days and cold temperatures during these months results in significantly lower temperatures than during the summer.