You know… I probably run in the most extremes of anybody as far as temps, and in general I cant say I have noticed more than 1-2 mph difference between running 48 degree water with airtemps around 20 and running in 90 degree water with air temps pushing the 120 mark. Oh, dont get me wrong. I always felt my outboard sounded better on a cool crisp winter morning, and I have seen very measurable differences on a dyno with motorcycles. It does seem to me that on hot days with high humidity I see another 1-2 mph difference. That may not be a distinction for many people though. I happen to run in one of the few areas with relatively low humidity in the summer times… well until the monsoon weather rolls in, usually in late July or early August. Hence when I see the additional difference. Of course this is all relatively subjective as the boat is never balanced the same, and the load is never the same. P.S. For us high humidity is anything over 40%. Normal is around 20, and maybe 25-30 along the river. For example. Right now the humidity is 41%, the monsoon weather has started this year already (there were flash flood warnings to the north yesterday), I am about ten miles from the river as the crow flies, and I am surrounded by citrus and alfalfa fields on all sides. For us desert rats thats considered high humidity. I would expect it to be over 50% on the river right now. Other parts of the country would consider that normal or even low.–Bob La Londe Forums, Free Lures, Product Reviewswww.YumaBassMan.com CNC Molds N Stuffwww.CNCMOLDS.com