You have old data in your database from weewx running before your clock was corrected by ntpd or systemd.
See the wiki article " https://github.com/weewx/weewx/wiki/Cleaning-up-old-'bad'-data" for the procedure to fix things. You want to search for dateTime < 1000000000 which is in 2001 so it should be a reasonable starting point. I would suggest installing ntp rather than relying on systemd to keep the clock in synch (sudo apt-get install ntp) -- 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 weewx-user+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/weewx-user/ad18e484-c16b-4385-a552-6eb10925ecdan%40googlegroups.com.