It was exceptionally windy. I don't have data specifically for St. Andrews, but I was able to find data from RAF Leuchars, just across the Eden Estuary from the Old Course at St. Andrews.
I downloaded (from Weather Underground, as described here), the daily wind speed data for every July day since 1 July 1996. That is, 607 July days from the start of July in 1996 through 18 July 2015. Twenty years of July days.
In these 607 days, yesterday had the highest mean daily wind speed, 42 km/h, by a wide margin. In fact, the next closest day had average wind speed of 32 km/h.
These data, from the most recent twenty years, show that the wind speeds of 18 July 2015 were extraordinary.