Answer 1 of 2.
Breaker trips when it rains. There could be a short circuit in one of the appliances or somewhere in the wiring. Answering from USA wiring perspective. The breaker cannot be reset until everything has dried up.
Keep in mind though that even if a piece of equipment that IS plugged in is causing the GFI to trip when it rains that may not necessarily mean the equipment is faulty. It is dangerous to have a broken power point. Every time it rains a main GFI breaker trips before individual circuit breakers trip.
When the breaker senses the current leakage it trips to protect you and the. In most instances moisture in the electrical box housing the GFCI breaker is the cause for the GFCI breaker tripping. There is always the one breaker.
To ensure that this doesnt happen you should use lights labeled for exterior use. Secondly how do you keep Christmas lights from shorting out in the rain. Our GFCI breaker will trip during heavy rain.
You simply open the door on your homes service panel breaker box and press the test button on the GFCI breaker. Can rain cause a breaker to trip. GFCIs protect you from electric shock.
Im thinking the problem lyes there but could do with a bit of advice to testing it. Every time is rains the house trips and we jump into the usual method of all breakers down mains down then up and continue to push other breakers up one by one. Your exterior outlets should also have a ground fault circuit interrupter GFCI.

