There's certainly been a gradual increase in traffic over the decades, but I'm really not sure it's a "huge increase" in the last year.
Ask people from the area then.
Is the weather better this year (fewer clouds) than in previous years and therefore the trails are more visible?
No, much more cloud an overcast that previous years and certainly not like being shown on national, regional and local weather, yet just a couple of miles away and totally different, at the same time.
Have you changed jobs/working hours and are "spotting" at peak times?
No to job/working. Times vary and on a like for like basis.
As for the reliability of the "radar sites", no they don't show everything.
So that simple statement could be a possibility?
Could be seven up there but nothing showing with 50 miles.