Why does sound seem so much clearer, carry farther, and/or so utterly silent in cold temperatures?
In: Earth Science
temperature and humidity both affect how much sound is absorbed, but this also depends on the *frequency* of the sound. i linked an interesting paper on this, just skip ahead to the graphs on page 25 onward if you don’t feel like reading it. i will do my best to summarize the graphs, but this is difficult because they relate many different factors (temperature, frequency, humidity).
it says that at standard temperature (20C), absorption is greatest at 20% humidity, and that there is more absorption for *high frequency*. ie, at 20C, and 20% humidity, air will act like a high pass filter, attenuating high frequencies, but letting low frequencies pass through. in general, absorption is measure in dB/m, meaning how much energy is lost per meter of travel.
moving on to temperature. at *low frequency*, lower temperatures absorb sound more, at lower humidity, while high temperatures don’t have much of any effect on low frequency at any humidity. so to rank from loudest to quietest: high temp > low temp high humidity > low temp low humidity.
this interaction changes immensely for *high frequency*. here, absorption is greatest at high temperatures with low humidity, and lowest at low temperatures with high humidity.
let’s summarize these results and tie them back to your questions. i assume you’re talking about low temperatures with low humidity. these conditions favor the transmission of high frequency the most, adding to what would be called a “clear” sound, as these frequencies are where voices and other important sounds live. lower frequencies are not as favored by these conditions, this would probably add to the effect of “quietness” as there is less ambient rumble, whatever that may mean.
these findings are most applicable for long range sound reinforcement, outdoor theaters, large festivals, etc. but they are also true anywhere. the effect however won’t be seen at smaller distances, as the air just won’t have enough time to properly attenuate any of the sound. i am sure that other factors mentioned in this thread, including speed of sound, atmospheric reflection, and snow absorption also play a huge role, but i wanted to outline another important factor.
[https://ntrs.nasa.gov/api/citations/19670007333/downloads/19670007333.pdf](https://ntrs.nasa.gov/api/citations/19670007333/downloads/19670007333.pdf)
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