Air temperature, altitude, barometric pressure, humidity, etc. all can effect rwhp numbers from dyno machines. The only value that you can really count on with a Dyno is your power curve. It will tell you where the bike is running good and where the bike is running poorly. Most people who are big time racers know that they have to tune their car or bike to the conditions of that day or for drag racing...That moment. If you want to get really good horsepower numbers or really bad horsepower numbers just play around with the correction factor.
I dynoed my bike last Friday and here are my results.
95.5 pound feet of torque @ 7,000rpm
153.9 rear wheel horsepower (RWHP) @ 9,500rpm
Temperature was 90 degrees
Absolute barometric pressure was 30.13 in.hg.
Vapor pressure .55 in.hg
Correction factor was 1.02