I was hand flying an ILS to 22R with a sidestep to 22L last week with surface winds reported as calm. Not a cloud in the sky. This was about the 3rd or 4th day in a row of light winds and clear blue skies (and warmer than usual temps). The 737 landing ahead of us reported a gain of 20kts at 500' on approach. I was deliberately staying a half dot high on the glideslope to not hit his wake. Even still, it was bumpy all the way out from about 20 miles NW
, all the way to touchdown (surface winds calm???). I know that a lot of it has to do with the topography with heat radiation thermals, especially as the day goes on. I think you'll find that earlier in the day, approaches are smoother, and the mid to late afternoon is the worst for turbulence. Also, at EWR
, you have many industrial plants that give off steam/waste heat/other pollutants that indirectly create turbulence.
There are 3 types of people in this world, those that can count, and those that can't.