Note that this is in Thailand where there are no rules.
My home has a main breaker which includes a GFCI. Recently the breaker has started to trip when it gets cold. (This is Thailand. Cold means around 20ºC or about 68ºF).
I have isolated this to one circuit. When I turn that circuit off, the main no longer trips. I have tried unplugging everything on that circuit and turning all the lights off. It still trips at night when it's cool. The next morning when I turn that circuit back on, all is well. If the nights are warm, the breaker doesn't trip.
Any ideas?