Bottom brackets have evolved from unsealed cup and cone, to sealed cartridge units, Separate industrial sealed bearings inside the BB shell, to the current manifestation of industrial sealed bearings held in external cups.
The most weather resistant are Shimano style cartridge units, which can go for a number of years in everyday, all-weather use, even in the cheap versions.
Modern external BB units depend on accurate, parallel facing of the BB shell and have a reputation for poor durability in harsh conditions. People often quote their use by professionals as evidence of their durability, but they ride well-aligned bikes with regular professional-grade servicing. An everyday, commuter hack in a rainy winter, or a mid-range MTB used in wet, muddy conditions every weekend is a harsher test.

Most BBs can be made more longlasting by drilling a water drainage hole in the shell (metal, not carbon fibre!)