hi, so much differences in reported conditions...why?

Currently under a Yellow Wind Warning.

UAV 4 m/s at 50m, 13 m/s gusts at  50m
Ventusky: 3 m/s at 100m, 2 m/s gusts at ground level

Actually, UAV is the most correct as I can feel from my open window (1:06 AM as I am writing, valley, town area) powerful gusts of wind on my 1st floor (by far more powerful than a MM wind standing capability), with prolonged times of calm wind.

I guess it's quite challenging to pinpoint the exact conditions during Spring/Fall switfly changing weather. Today must have been clearing from the afternoon (per local weather forecasts) and it was only during late evening.

Because they are just forecasts and get data from different sources.
No forecast can be relied on to tell you what actual conditions are at your location.

Use them as a guide. Also make sure you set the height in UAV forecast where you will be flying at because that's where the drone will be. It's not as strong at ground level as it is 120m up in the air.

I like Uavforecast, it shows the weather quite correctly in my area.
And the difference in data depends on the service that provides them, the better equipped it is, the more accurate the data.