That seems like a nice safe approach for others who need to do the same 
thing.

I ended up doing something like this with a few side trips involved. 
Stop weewx
backup weeewx db
Setting the clock_check value really low
change timezone on the host
start weewx
check logs for errors
revert clock_check value
restart weewx.

Thanks for the suggestions!

Blake

On Sunday, October 16, 2022 at 7:57:26 PM UTC-7 vince wrote:

> I'd probably approach it ala:
>
>    - stop weewx and back up the db(s)
>    - probably set debug=1 in weewx.conf to make logs more helpful
>    - set the os system timezone as desired.  I think the magic 
>    incantation is 'sudo timedatectl set-timezone "America/Los_Angeles"  and 
>    if you run a full desktop there's a gui utility to do this as well.  One 
>    howto link is 
>    https://tecadmin.net/how-to-change-timezone-on-ubuntu-20-04/ - your 
>    syslog should show the date+time changed to your local timezone 
> immediately.
>    - I'd then set the console timezone manually at the Davis console. 
>     The manual is at 
>    
> https://www.weathershack.com/products/davis/manuals/vantage-pro2-console-manual.pdf
>  
>    which is pretty clear
>    - I'd personally shut the system down (full poweroff via 'sudo 
>    poweroff' or equivalent) and then power it back up
>    - The os should set its clock via systemd (or ntp if you have that 
>    installed) and weewx should wait until it has sane time before starting.   
>    The logs will tell you what's going on.
>    - my recollection is weewx has no notion of timezone, but it's unclear 
>    to me what datestamps (if there are any) are in the records stored in the 
>    datalogger.  Given that the above should take only a minute or three to 
>    accomplish, I'd hope you won't lose any observations....but that's why we 
>    take the backups just.in.case.
>
>
> On Sunday, October 16, 2022 at 6:00:16 PM UTC-7 [email protected] 
> wrote:
>
>> OK I (backed up the db again) set the system timezone back to US/Pacific 
>> and then set the following down to 30 sec. 
>>
>> [StdTimeSynch]
>>   clock_check = 30
>>
>> I got these messages on the log shortly after service start.
>>
>> Oct 16 17:52:49 wx python3[780]: weewx[780] INFO weewx.engine: Clock 
>> error is -24.57 seconds (positive is fast)
>> Oct 16 17:52:49 wx python3[780]: weewx[780] INFO weewx.drivers.vantage: 
>> Clock set to 2022-10-16 17:52:50 PDT (1665967970)
>>
>> The "* WARNING weewx.engine: Ignore historical record" * messages have 
>> now stopped on the log..
>>
>> I ended up with some bad data in the db from what the reports show. 
>>
>> On Sunday, October 16, 2022 at 5:32:29 PM UTC-7 Greg Troxel wrote:
>>
>>>
>>> Blake Garner <[email protected]> writes: 
>>>
>>> > I want to change the timezone from UTC to Pacific time display in 
>>> local 
>>> > time on my weewx website. From reading, it seems that weewx uses the 
>>> system 
>>> > time and it's not configurable at the application. After changing my 
>>> system 
>>> > timezone to US/Pacific I'm seeing this message spew in the logs. For 
>>> now I 
>>> > flipped the timzone back until I have a better idea of what's going 
>>> on. 
>>> > 
>>> > Oct 16 23:24:38 wx python3[2833293]: *weewx[2833293] WARNING 
>>> weewx.engine: 
>>> > Ignore historical record: {'dateTime': 1665970800, 'usUnits': 1, 
>>>
>>> $ TZ=UTC date -r 1665970800 
>>> Mon Oct 17 01:40:00 UTC 2022 
>>>
>>> So without knowing what the highest value is, hard to interpret. 
>>>
>>>
>>>
>>> I'm not totally clear on this, but I think what's happening is: 
>>>
>>> database is always in UTC 
>>>
>>> VP2 does not have a protocol that is always UTC and display localtime; 
>>> it fundamentally operates in local time 
>>>
>>> driver infers VP2 clock time as local time, in this case UTC 
>>>
>>> Yes, report generation follows timezone 
>>>
>>> My weewx machine (RPI3, NetBSD 9, with VP2) is set to EST5EDT. 
>>>
>>>
>>> So therefore I guess that your VP2 is running in UTC, even if it thinks 
>>> it is s PST8PDT which might mean that the data in the database is 
>>> correct, but 
>>>
>>> - the time on the console is 7 hours ahead (now) 
>>> - the daily high/low values are not for localtime midnight-midnight 
>>> - the data in the database is actually right. 
>>>
>>> - I have no idea what's going on with console DST settings. 
>>>
>>> To recover, I wonder if you need to somehow pause the console for 7h. 
>>> Or if just changing the time on the console as you flip the TZ is 
>>> enough. 
>>>
>>> Or if I'm wrong about labeling on database records being ok, and you 
>>> need to do surgery. 
>>>
>>> I'm sure someone has had this problem; definitely wait for better 
>>> advice, but this may give you things to think about and try to 
>>> understand, even if my guesses are a bit off. 
>>>
>>> Definitely back up your database right now, and also before you tried to 
>>> change the TZ the first time :-( 
>>>
>>

-- 
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 on the web visit 
https://groups.google.com/d/msgid/weewx-user/24fc1757-03da-47b5-bd6e-fa8411bc281an%40googlegroups.com.

Reply via email to