I recently downloade the Beta 2 version of Vasari. I like using it to generate wind diagrams. I selected my location and then opened the wind rose. I notice the wind speeds seemed to be high. I changed the units from m/s to knots to see if that would adjust the excessive speeds. It did not. I changed sites to see if it was the location and found the same issue. I then compared to other wind data and the wind rose in Revit. I found that the directional winds matched, but the speeds did not. Is this a matter of uninstalling and reinstalling? 
That is correct. The speeds in Vasari are reading way high. It started with analysis for Atlanta. it was showing their average wind speeds in excess of 20mph with high end averages of 60+. Obviously the numbers were showing in knots and/or m/s. When I converted them is when i realized they were high. That's when I ran the analysis in Revit to see the readings and was able to confirm the high values. I also double checked the average monthly speeds with several different websites.
Brian, thanks for bringing this to our attention. So just to clarify, the wind speeds you see from the Revit Results and Compare window seem more accurate than those in the Vasari Wind Rose for Dallas? That would help us track down the culprit.