we have a GFCI breaker in our breaker box. On that circuit are the
lights and outlets in two bathrooms and the garage door opener. I'm
not sure if anything else is on the circuit.

Intermittently, the breaker has been tripping (usually in the middle
of the night or when we are at work during the day). When I reset the
breaker, it stays on. This has recently been happening on a frequency
of between twice per day to once every few days. At night we have a
night light on in one bathroom, but during day I can't think of
anything on this circuit that would be drawing a current

One time it tripped when I was actually at home, and I found that when
I tried to reset the breaker that it would immediately (within a
second or two) trip again - but after about 10 minutes I was able to
reset it and it stayed.

I'm not sure how to diagnose the cause of this problem if whatever is
causing the short will not stay shorted.

There used to be two outdoor outlets on the circuit - but I discovered
that whenever we had a hard rain, moisture would get into those boxes
(which were no longer well sealed) and cause the breaker to trip - it
could not be reset until the moisture was gone. Those outlets have
since been removed, so are not the cause of the current problem.

Also, this has been happening recently during a period of bone-dry
weather.

Any help on how to diagnose this problem and resolve it greatly
appreciated.

Thanks.

-J