The saying: “Snow falls not as cold as when it melts” is a lesson learned from the elderly and is very
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When 1 gram of snow melts at 0 degrees Celsius, it absorbs up to 0.3 KJ of thermal energy (Photo: douglashunt) |
relevant to reality.
In order to have snow in winter, in addition to the sky needing to be filled with moisture (a few days before snowfall, the sky is often overcast), there must also be a certain low-temperature condition. Snowfall typically occurs when cold air moves southward, which is why the weather is not too cold during these days. When the cold air mass officially arrives, the sky clears up, clouds dissipate, and the snow stops falling. At this point, the temperature drops lower than on days with snowfall.
Furthermore, when the sky is clear and the clouds have cleared, a portion of the snow begins to melt. While the snow is melting, it absorbs a significant amount of heat from the air. According to scientists’ calculations, when 1 gram of snow melts at 0 degrees Celsius, it absorbs up to 0.3 KJ (kilojoules) of thermal energy. Therefore, snow causes the air temperature to drop, making us feel colder than when it is actively snowing.
