Impossible to say anything without more detail. What station do you have? What WeeWX version? What rtgd version? What does the log show? Please post a log extract showing the full WeeWX startup, this will give us a clear picture of your setup. Refer to the
Help! Posting to weewx user wiki page. Note the
How to view the log link if you are having difficulties viewing the log. Note also the need to set
debug = 1 in
weewx.conf.
How often does this occur? What was in the log when it last occurred? Please post a log extract from shortly (say 1-2 archive intervals in time) before the event through to shortly after the event (say 2-3 archive intervals in time). If relatively frequently it's worth leaving debug = 1 and when it next occurs post a log extract from shortly (say 1-2 archive intervals in time) before the event through to shortly after the event (say 2-3 archive intervals in time).
Gary