Chart problem

[Steve2Q]

Hello. I have not had a problem in quite a long time, but something cropped up, and I'm not sure where to start.

I have a Peet Bros station, and am running Weewx V 3.8.2. I found it does everything I want, so I never saw the point in upgrading. Anyway, this is the problem. 

I had to relocate my rain sensor. After starting up, I see that the graph for rain looks like the attached screen shot. Several years ago, I add the "Rain 2 minutes" the chart, and it worked fine until yesterday. Before relocating the rain sensor, I stopped Weewx and turned off the RPi that is running the program. When I started back up, the chart looks like this with the - rates. I don't know if a file got corrupted or where to start looking, I would appreciate any insight into what may be going on.  Thanks in advance.

[Tom Keffer]

Looks like you got some bad data in your database. See the wiki article Cleaning up old bad data. Its instructions are oriented towards V5.x, but you should be able to figure it out. The biggest difference is that you will use `wee_database` instead of `weectl database`.

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[Tom Keffer]

Hang on. The bad data goes back more than a year? That sounds like a lot more than a re-siting problem. 

It could be that your Peet station has been emitting bad data.

On the Peet Brother stations, rain is calculated as the difference in field "rain_total". For example, if the sensor has seen 0.23" of rain for the day, then with the next LOOP packet it goes to 0.25", then WeeWX records rain as 0.02" --- the amount of rain that must have fallen between LOOP packets.

It is possible that instead of rain_total increasing monotonically, it is going backwards, resulting in the large negative numbers you are seeing.

Set debug=1, then restart weewx. Let it run long enough to record a bad rain value. Record the time of the bad value in your notes, then post the log. Setting debug=1 will cause the driver to record the raw values coming off the station. If it takes a while to encounter a bad value the log will be voluminous, so you may want to upload it to pastebin.com or similar site.

-tk

On Thu, May 7, 2026 at 2:27 PM Steve2Q <ste...@gmail.com> wrote:

Dave; one question before I delve into this. The bad data extends back as far a one year (and maybe beyond). Will the clean up bad data procedure take care of it all?