Given the task definition and input, reply with output. You are given a background paragraph that describes one or more causal or qualitative relationships such as a relationship in economics or a scientific law and a story that makes use of the concepts or the relationship described in the provided paragraph. You need to come up with a question about the story that requires an understanding of the relationship described in the background paragraph. The generated question should not be answerable without both the background and story. Write a question about the story that requires a relationship in the background paragraph to answer. Check whether your question requires both the background paragraph and the story to answer. If your question can be answered by only one of these, try to rewrite your question so that it requires both. Note that "flipping" a word in the question can give rise to a new question where the answer will be different from the original question. Often, "flipping" a word gives rise to flipping the direction of the relationship, for example, from "increase" to "decrease."

Background Paragraph: Friction between the atmosphere and the Earth's surface causes a 20% reduction in the wind at the surface of the Earth.[10] Surface roughness also leads to significant variation of wind speeds. Over land, winds maximize at hill or mountain crests, while sheltering leads to lower wind speeds in valleys and lee slopes.[11] Compared to over water, maximum sustained winds over land average 8% lower.[12] More specifically, over a city or rough terrain, the wind gradient effect could cause a reduction of 40% to 50% of the geostrophic wind speed aloft; while over open water or ice, the reduction is between 10% and 30%.[8][13][14].
Story: The Johnson Family is planning a couple of excursions next week. On Wednesday they will be going to Tulsa Valley, and on Friday they are going to Albert's Peak, a small mountain in the area. Mr. Johnson has been wanting to fly some kites if there are some good wind conditions for doing so. He also wants to treat his family to a picnic and would like a more serene setting, with little to no wind to disrupt their picnic.
What day would be the best day for flying kites for the Johnson Family?