I am not sure if Pentax ever published the level of protection according to the IEC standard 60529 (IP Code, Internationally Protection Marking). My guess is it might be IP53.
But then again, in all fainess, these codes are typically suited as an acceptance criteria during final inspection of goods. You might want to check the test specifications, but these are difficult to translate into "real life" conditions.
Especially when users (like us) interfere with the integrity of the product ... in other words are changing lenses
At the end of the day it is mainly marketing and I would consider it as "a design with many seal should be better than a design without seals". In reality I dont treat WR lenses and cameras differently than non-WR equipment.
Both should work under "normal" circumstances and that includes some moderate rain or snow of course.