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Does wind blow from hot to cold areas or cold to hot? On the one hand, in general heat travels in the direction from hot to cold. On the other, I would imagine hot air to be less dense and so more likely to be the end point of wind.
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It seems like when the weather is cold, rain makes it warmer, but when the weather is hot rain makes it colder. Is this a true phenomenon, and if so, what causes it?
There’s something to this, at least in some areas. Rain is often (but not always) a result of a front moving through the area. Fronts are boundaries between two air masses with different qualities. Two common types are cold fronts (in which warm air is replaced by cold) and warm fronts (vice versa). When it’s warm, a cold front moving through will cause rain, then colder weather. When it’s cold, a warm front will cause rain, then warmer weather.
Another cause of rain in hot, humid areas (such as Florida in the summer) is air mass thundertorms. These are not associated with a front. After the thunderstorm, though, downdrafts cause temporary cooling. Again, it rains when it’s warm, and it gets cooler (for a little while at least).
There is a counterexample, though. Hurricanes tend to hit during warm weather, and certainly cause a good deal of rain, but they don’t tend to make it cooler after the rain.
Neither. Wind blows from areas of high pressure to areas of low pressure, but not directly. It spirals around them, outwards and clockwise from high pressure areas (“anticyclones”) and anticlockwise around and into low pressure areas (“cyclones”).
Take a look at a pressure map. The concentric lines are isobars, which link constant pressure. The faint wind arrows underneath show the direction and strenght of the wind (the more “feathers” on the arrow, the stronger). You can see that where the isobars are closest together, that’s where the wind is strongest, and it blows almost along the isobars, but slightly deflected towards the low pressure side. It’s like contour lines on a topo map - the closer together, the steeper the terrain.
It’s not as simple as that. In hot weather, yes, rain tends to cool the air by evaporation. In winter, though, very cold weather tends to be accompanied by clear skies, which allow for frosty nights. Cold air can hold less water than warmer air, too, so when rain does arrive it is usually because warmer, moister air has moved in.