|MadSci Network: Earth Sciences|
The answer to your question is actually quite simple. Air always flows from high pressure to low pressure. This is how wind is formed. As the ground heats up, the air rises, causing a low pressure area. The lake now has a relatively higher pressure. The wind will flow from the lake to the shore, which is why it seems as though the wind is always in your face. If however, you were to go to the lake when it was warmer than the air, the opposite would be true, and there would be a gentle breeze from the land to the water. This generally occurs late at night. As an owner of a sailboat, there is no breeze that is better. I can always count on wind at night from the shore to the water to help me. Try going to the lake late at night, and you should feel it. Please remember, however, the greater the difference in temperature and pressure, the stronger the wind. If the lake and shore are about the same temperature at night, the wind will be very mild. If you are interested, take two styrofoam cups, place them next to each other, and stick a pencil through their sides. Turn one of the cups so that they are facing opposite directions. Then tie a piece of string to the pencil between the two cups, and you now have a crude anometer. Hold the cups in the air, and you will see the wind direction. Hope this helps. John O'Sullivan
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