If the rain collector has debris in it and fills with water, could a constant trickle via seepage around the debris cause this? Likewise, if the collector is clear and then is filled full from a pitcher, could that cause the extreme in/hr rate?
On Tuesday, November 4, 2025 at 3:19:48 PM UTC-6 vince wrote: > Thanks. I can only think of a loosely attached or vibrating tipper > bouncing on and off the post it tips onto, perhaps in gusty wind or > whatever it’s attached to shaking. I see a lot of 82.29 in/hr rates which > seems to be some Davis max they can come up with. > > 0.13” in 5 minutes is 1.56 in/hr if it was steady tipping rate, not 82.29 > in/hr reported > > 0.09 in 5 minutes is 1.08 in/hr at steady tipping, ot the 64.00 reported > > Really odd. Would it be wise to define some StdQC item for this station ? > > On Tuesday, November 4, 2025 at 12:35:28 PM UTC-8 Tom Keffer wrote: > >> The VP2 has hardware generation. So, unless the user changes something, >> the database will record whatever comes off the console. As for how Davis >> calculates rain rate, here's what they have to say in their "Derived >> Variables >> <https://support.davisinstruments.com/article/igpcv664kz-app-notes-derived-variables-in-davis-weather-products>" >> >> document. >> >> RAINFALL RATE >> >> Parameters Used: Rain Total (actually, rain rate is a measured variable >> in the sense that it is >> >> measured by the ISS and transmitted to the display console, whereas all >> other calculated >> >> variables are determined by the console from data received from the ISS.) >> >> Formula: >> >> Under normal conditions, rain rate data is sent with a nominal interval >> of 10 to 12 seconds. >> >> Every time a rain tip or click occurs, a new rain rate value is computed >> (from the timer values) >> >> and the rate timers are reset to zero. >> >> Rain rate is calculated based on the time between successive tips of the >> rain collector. The rain >> >> rate value is the highest rate since the last transmitted rain rate data >> packet. (Under most >> >> conditions, however, a rain tip will not occur every 10 to 12 seconds.) >> >> If there have been no rain tips since the last rain rate data >> transmission, then the rain rate based >> >> on the time since that last tip is indicated. This results in slowly >> decaying rate values as a rain >> >> storm ends, instead of showing a rain rate which abruptly drops to zero. >> This results in a more >> >> realistic representation of the actual rain event. >> >> If this time exceeds roughly 15 minutes, than the rain rate value is >> reset to zero. This period of >> >> time was chosen because 15 minutes is defined by the U.S. National >> Weather Service as >> >> intervening time upon which one rain "event" is considered separate from >> another rain "event". >> >> This is also the shortest period of time that the Umbrella will be seen >> on the display console >> >> after the onset of rain. >> >> On Tue, Nov 4, 2025 at 12:21 PM vince <[email protected]> wrote: >> >>> Tom - how could weewx generate bizarre rainRate values in an archive >>> record when the amount of rain in an interval period looks reasonable ? >>> The station is a VP2. >>> >>> Here's one example related to that other long thread 'Correct Old and >>> New Rain Records'. >>> >>> sqlite3 query was: >>> >>> echo "SELECT interval,datetime(dateTime,'unixepoch','localtime'), >>> dateTime, rain, rainRate FROM archive where dateTime<1570838400 and >>> dateTime>=1570752000 ORDER BY rainRate DESC LIMIT 10;" | sqlite3 >>> ~/weewx-data/archive/weewx.sdb >>> >>> Just the interesting archive records.... >>> >>> 5|2019-10-11 21:45:00|1570830300|0.0|0.0 >>> 5|2019-10-11 21:50:00|1570830600|0.0|0.0 >>> 5|2019-10-11 21:55:00|1570830900|0.13|82.29 <== >>> 5|2019-10-11 22:00:00|1570831200|0.09|64.0 <== >>> 5|2019-10-11 22:05:00|1570831500|0.0|0.07 >>> 5|2019-10-11 22:10:00|1570831800|0.0|0.04 >>> 5|2019-10-11 22:15:00|1570832100|0.0|0.0 >>> 5|2019-10-11 22:20:00|1570832400|0.0|0.0 >>> >>> Total for that day was 0.23" so basically all was in that 10 minute >>> period >>> >>> Other than a possibly broken/chattering tipper sensor, can you think of >>> anything ? >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "weewx-user" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> To view this discussion visit >>> https://groups.google.com/d/msgid/weewx-user/e4e40f72-528a-4962-85f9-206b4d6f1212n%40googlegroups.com >>> >>> <https://groups.google.com/d/msgid/weewx-user/e4e40f72-528a-4962-85f9-206b4d6f1212n%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> >> -- You received this message because you are subscribed to the Google Groups "weewx-user" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion visit https://groups.google.com/d/msgid/weewx-user/f74a77a3-5c16-4085-a270-1c9b0f666857n%40googlegroups.com.
