Whatever is actually falling where you are, turned into a sound. Nothing here is a recording — every drop is made up out of noise and a filter at the moment you hear it.
Finding out where you are…
The reading is real and the sound is not a recording. Your rough position comes from
the same keyless /api/where the desktop's weather widget uses — city level at
best, nothing stored — and the weather itself from
Open-Meteo, which needs no key.
Weather data by Open-Meteo.com, used under CC BY 4.0. The panel above prints the
actual millimetres and the actual WMO code rather than a word chosen to match the sound.
How millimetres become a noise. The intensity bands are the standard meteorological
ones, not invented: under 2.5 mm/h is light, 2.5–7.6 is
moderate, and over 7.6 is heavy. That number sets five layers, all generated here:
a wide band of filtered noise for the hiss of many drops at once; a mid band around
600 Hz for the body of it; a low brown-noise rumble that only comes in when it
is really coming down; individual droplet impacts, scheduled at a rate that follows the
intensity, each a few milliseconds of noise through a sharp resonant filter; and the occasional
slower plink of water falling into water that has already collected.
When it is not raining you get a clear-sky hum instead — two sine tones a fraction
apart, beating slowly against each other, under a breath of filtered air. An empty panel would
be the honest thing to show and a bad thing to listen to. Thunder is only ever armed when the
real WMO code is one of the thunderstorm ones (95, 96, 99),
so you will not get a storm that is not happening.
The slider moves the sound, never the reading. Wherever you push it, the panel goes on saying what is actually falling on you.