Yesterday I noticed Weatherlink.com was not displaying my data.  iPhone app was okay. Today all looks okay:

ok, good job, update the ws90 to the latest firmware version, then do the calibration with the CAL button in a room, without wind, then re-install everything outside and let us know how it goes

I never calibrated my ws90, but it does go to zero when there is absolutely no wind.

Upgrading the firmware will make all the data I've got so far essentially useless so unless there is something wrong I know this will fix with the sensor I'm reluctant to upgrade.

The change log says there is "enhanced accuracy" and "wind sensor optimisation". What I'm seeing is does not look like inaccuracy, it is an almost constant offset of 0.9 to 1.3 m/s.

I started this thread to find out if this is what these sensors do... Maybe this is caused by the rotating sensor inertia and high end ultrasonic sensors compensate for it?

Unless someone here has a WS90 and a ws68 (or another rotating sensor). I doubt we'll know.

You need to contact support@ecowitt.com and tell them your issues - they should be able to sort it out

I think you are missing the point of the context of the post ...
Maybe read it again from the beginning.
While the advice might be good in a general context, it might not really be in this case.
When you wake up sleeping dogs, don't be amazed when they bark and bite.

Which one are you running the schedule on Oliver ?

You need to contact support@ecowitt.com and tell them your issues - they should be able to sort it out