Please note the following:
Stanwell Park is flyable in winds SSW to East.
E - ENE - NE wind speeds read low due to shadowing affect of trees.
Rotor in N - NW - SW & Strong gusty S - SE winds cause the direction vane to flick around.
When the wind is ESE and thermic the vertical component causes the wind speed to read low.
Moderate SSW - S - SE & ESE winds are reasonably accurate.