weather seal on the new 1.4 primes
I have all three and none of the "breathe" or having any sort of moving exterior parts.
No lens, even what you are calling "weather sealed" lenses should be in prolonged heavy rain without protection. Yes they have a rubber gasket near the mount end of the lens disassemble any lens and that is pretty much the extent of it - there are no internal rubber seals or something like that.
Can you take these lenses in rainy/wet conditions most of the time and be ok? Probably - but it's a gamble.