I wonder what is the source for the speeds?

How often are they updated?

One thing I have noticed is where the socks are close to the runway, the windsock is obscured by the runway if its blowing across (see image I snapped a while back). Makes it a little difficult to work out the direction.

thanks for this windsock feature, its really handy when planning, and flying.

If you want to see the actual or forecast surface wind at an airfield, just look at the Approach Information in the Airfields tab.