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Speaker 1: Welcome to Brainstuff from house stuff works dot com where

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Speaker 1: smart happens. Hi Am Marshall Brain with today's question, if

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Speaker 1: the temperature is thirty degrees fahrenheit outside, why do we

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Speaker 1: sometimes get snow and other times we get freezing rain.

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Speaker 1: When you watch the local weather report on the evening news,

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Speaker 1: you always hear the current temperature. It may be, for example,

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Speaker 1: thirty two degrees fahrenheit or zero degrees celsius outside. That's

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Speaker 1: useful information, but if it's precipitating, it is only one

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Speaker 1: part of the puzzle. It turns out that the atmosphere

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Speaker 1: is layered, and these layers control the form that precipitation

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Speaker 1: will take on the ground. The local weather report only

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Speaker 1: gives us the ground level temperature. In order to understand sleet, snow,

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Speaker 1: and freezing rain. What we need to know is perhaps

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Speaker 1: four to six different temperature readings at different altitudes. Precipitation

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Speaker 1: starts in the cloud as snow. As it falls, it

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Speaker 1: may travel through a layer of air that has a

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Speaker 1: temperature greater than thirty two degrees fahrenheit. This layer melts

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Speaker 1: the snow into rain. If the temperature at ground level

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Speaker 1: is below freezing, then the water may refreeze in the

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Speaker 1: air and then we get sleep. Or if the layer

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Speaker 1: of subfreezing air at ground level is thin, the precipitation

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Speaker 1: falls as rain, but then it freezes once it touches

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Speaker 1: the freezing object on the ground. For snow to fall,

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Speaker 1: all the layers of air that the snow falls through

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Speaker 1: once it leaves the cloud must be sub freezing. The

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Speaker 1: warm middle layers are normally caused by the movement of

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Speaker 1: warm fronts or cold fronts through the area. In the southeast,

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Speaker 1: temperatures often hover around thirty two degrees Fahrenheits, so the

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Speaker 1: form of precipitation can change all the time. In more

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Speaker 1: northern areas, the temperature is well below freezing in all

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Speaker 1: the layers, so snow is a sure thing. You have

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Speaker 1: any ideas or suggestions for this podcast, If so, please

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Speaker 1: send me an email at podcast at how stuff works

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Speaker 1: dot com. For more on this and thousands of other topics,

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Speaker 1: go to how stuff works dot com and be sure

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Speaker 1: to check out the brain stuff blog on the how

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Speaker 1: stuff works dot com home page.