Rainfall granularity

With the latest app update, the Siri Shortcut “Detailed current conditions” now reads daily precipitation out to five decimal places (when using inches - I presume millimeters behave similarly.) After being bemused about this, I realized just how granular Tempest’s rainfall measurements really are. We have had very light rain or drizzle much of today, much of which was too light to register even as “Very Light” on the app. Yet the precipitation was recorded. As of 9:26am, the Shortcut read precipitation accumulation as 0.000566 inches; the Tempest app showed accumulation as Trace. The app recorded 0.01” at 9:55am. Later in the day, at 7:260pm, the Shortcut reported daily precipitation as 0.012446 inches; the app was still (appropriately) reporting the daily total as 0.01”. Lots of words to say I’m impressed with the level of granularity recorded in the background even with very light precipitation.

hello do you mean the sensor registers fine rain even if it is not activated?

Clearly the Tempest is recording very fine amounts of rain as they happen, even if the frequency and/or force of impacts upon the haptic sensor is below the threshold to show as Very Light.

thank you so it is able to record the drizzle :slightly_smiling_face:

I’m not seeing any rain readings on my Tempest. We’ve had a fine misting drizzle all day. My tube gauge shows a small accumulation, and WesterUnderground shows other make nearby gauges measuring small (less than .1 inches) throughout the day. But neither my new Tempest nor two others in the neighborhood are detecting any rain at all today.

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pity I think that with the last update: does it mention the ground track on the graph?

I’ve had exactly the same experience and posted about it in another thread (Haptic sensor not detecting rain). I received a reply advising that the haptic sensor detects the vibration of raindrops impacting on the unit so will not detect very light rain. If you give the mount a few taps (I used a broom handle) then it will likely show as rain.

It is frustrating that the Tempest is unable to detect light rain and I’d really like to know just how big droplets need to be before being detected. I as outside when it was raining lightly earlier in the week and I could certainly feel that impact of raindrops but the Tempest couldn’t.

You should check if your battery level is heigh enough as Tempest stops his sensor below a certain voltage.

Mine is at 2.7V so should be OK. Lots of sun and very little rain here lately (which is why it would be nice to know what little rain did fall)

I’ve just watched a storm hit with heavy rain yet my Tempest took ages before it registered anything while other weather stations in my area were all showing heavy rain. The Tempest eventually showed a little rain but 0.4mm/hr vs around 20mm/hr for other nearby stations. It’s difficult not to conclude that this device is almost useless at detecting rain which is very disappointing.

of course the granularity is extremely fine. Basically it measures each single drop.
However if the drop doesn’t make enough “noise” when hitting the top, it will go undetected.

even the sensor set to none lower than very light, then when the sensor activates its accounting again?

I think it might start counting at the second drops it hears within a short period of time. The first drop is probably ignored to reduce the amount of false rain detections.
A singe drop with a diameter of 4mm adds only 0.0000034 to the amount reported in mm of rain/m2

thank you for these details :slightly_smiling_face:
I just did a test: precipitation on the sensor inf 01 / 1.2mm no detection, duration of precipitation about twenty minutes then rain greater than 1.2 mm / h, sensor becoming functional and on the board via photo: cumulative precipitation he displayed (trace) so I concluded that he has accumulated the lower rain not detected before and the new ones in progress