Thanks Gary. Do you have an explanation for this:

I got hit by a Super Cell thunderstorm some weeks ago which delivered ~25mm 
in about 15 mins. Max rain rate for this month was those 25mm:

archive_day_rainrate
dateTime    min  mintime          max    maxtime     sum              
 count  wsum                  sumtime
1624312800  0.0  1624312803       25.28  1624395078  376.134682539682  288  
  112840.404761905      86400

select datetime, rain, rainrate from archive where datetime between 
1624384800 and 1624399200 ORDER by datetime DESC
dateTime    rain                rainRate
1624393200  0.0                 25.02
1624392900  0.0                 25.02
1624392600  1.03199999999924    24.737
1624392300  6.19200000000092    21.512
1624392000  17.2860000000001    8.48545454545454
1624391700  0.515999999997803   0.076
1624391400  0.0                 0.0

gjr80 schrieb am Mittwoch, 28. Juli 2021 um 14:30:52 UTC+2:

> WeeWX calculates rainRate by summing the rain seen in the last 900 seconds 
> (15 minutes) and scales this to a per hour figure by multiplying by 
> 3600/900. So your 21.8 mm appearing in one packet/record would have 
> resulted in 21.8. * 4 = 87.2mm/hr; exactly what you saw. Due to the 900 
> second window being used the 87.2 mm/hr value would have persisted for up 
> to 15 minutes. The 34.9 value may have been the result of when the 21.8mm 
> value arrived, impossible to say without seeing the exact loop 
> packet/archive record history. You can change the 900 second window to some 
> other value, say 600 seconds (10 minutes) and WeeWX would then take the 
> rainfall seen in the last 10 minutes and scale that figure to a per hour 
> figure (in that case multiply by 3600/600).
>
> This is covered in the [[RainRater]] 
> <http://www.weewx.com/docs/usersguide.htm#%5B%5BRainRater%5D%5D>stanza in 
> the User’s Guide. Note the Userks Guide states that 1800 seconds (30 
> minutes) is used by default for the window but the code actually uses 900 
> seconds. Must fix the documentation.
>
> Gary
>
> On Wednesday, 28 July 2021 at 22:10:21 UTC+10 wysiwyg wrote:
>
>> Hi !
>>
>> I have a situation where I'm not sure about weewx behavior and how to 
>> deal with it :-).
>>
>> I have made my own rain sensors: It reports rain every 2min30 and reports 
>> 0mm when there's no rain.
>> Rainrate calculation is not done and not emitted by the sensor: Weewx has 
>> to handle it.
>>
>> Now come a situation: My sensor crashed yesterday and did not reported 
>> anything over the night (it was raining).
>> I rebooted it a few minutes ago, without power cycle, so I don't loose 
>> the rain counter of the night => the sensor sent 21.8mm from the whole 
>> night in one shot.
>>
>> I would expect that the rainrate shall not be calculated...or maybe shall 
>> be calculate with a time span between last and previous sample (yesterday 
>> before it crashed).
>>
>> it seems not working this way as weewx reported:
>> - 34.9mm/h at next report following the 21.8mm record.
>> - 87.2mm/h the following report 5min later.
>>
>> I assume maybe weewx consider "not rain data" = "0 mm of rain" ?
>>
>> I have a couple of questions:
>> - Is this behavior expected or maybe it's something that could be 
>> improved ?
>> - Can I delete those rainrate sample from database ?
>> of course my daily rain graph is a bit weird, but I want to keep the 
>> 21.8mm (so monthly or yearly records are ok), but I don't want to have my 
>> yearly/alltime max rainrate using this wrong data.
>>
>> best regards,
>>
>>
>>
>>
>>
>>

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