If a circuit breaker trips specifically when it rains or right after a storm, the most likely cause is moisture getting into an outdoor outlet, light fixture, junction box, or exposed wiring connected to that circuit. Water is conductive, and even a small amount seeping into a connection can create a short circuit or a ground fault, which trips the breaker as a safety response. This is different from a breaker that trips randomly with nothing plugged in, which often points to the breaker itself wearing out.
The most common culprits are outdoor GFCI outlets, exterior light fixtures, doorbell wiring, or a weatherhead where the main power line enters your house. If the outlet or fixture cover isn't properly sealed, rain can drip in through gaps around screws, cracked gaskets, or a cover that doesn't close all the way. Over time, UV exposure and temperature swings degrade rubber seals and plastic housings, making leaks worse each season.
Another frequent source is a damaged or aging weatherhead, the metal cap where the utility's service wires connect to your home. If the seal there fails, water can run down inside the conduit and into your main panel or a nearby circuit, which is more serious because it affects a larger portion of your home's wiring, not just one outlet.
Underground wiring is a third possibility, especially for circuits feeding sheds, detached garages, sprinkler systems, or landscape lighting. If the conduit has a crack or the wire nuts in a buried junction box weren't rated for wet locations, heavy rain or saturated soil can push water into the connections.
Attic or roof leaks can also cause this symptom if wiring runs through the attic and a roof leak drips directly onto a junction box or light fixture can. In this case the breaker tripping may actually be an early warning sign of a roof problem you haven't noticed yet.
Because any of these issues involve water meeting live wiring, this is not a safe situation to leave alone or to keep resetting the breaker and hoping it stops. Repeatedly resetting a tripped breaker without finding the cause risks arcing, melted insulation, or a house fire. Turn off the circuit at the panel if you can identify it, and avoid touching any wet outlets or fixtures on that circuit until it's been inspected.
For diagnosis and repair, call a licensed electrician rather than attempting to open a panel or outdoor box yourself, since locating moisture intrusion often requires testing with a multimeter and sometimes removing wall or ceiling material to trace the wet spot back to its source. An electrician can also confirm whether your outdoor outlets have proper GFCI protection and weatherproof "in-use" covers, which are required by code in most jurisdictions for a good reason: they're designed specifically to prevent this exact problem.