Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
Q: North america receives less direct sunlight during the winter is it winter in north america when it is summer in south america.
A:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Why is it winter in North America when it is summer in South America?