I've also read Kraigw's references to mirage. For that reason I don't doubt it usefulness.
However, mirage is a rare thing here, in Estonia.
It does not get especially hot, high 20's celsius being a toasty day, and the summer months are few in number. So, most of the time, mirage may not be as prevalent as one would like.
It is for that reason that I'm looking at any and all means, the Beaufort scale being the first one I've found.
Points about wind direction, as stated above, are very useful to add to that.
On a more serious note, if my walking around the neighbourhood with a wind meter and a range-finder ruins my hard-earned "man about town" image, I'll be blaming the members of TFL!!
