I'm in Spokane, it was roasting here Friday (104F) and they decided to let us go home at noon. And I have a 3.5-mile uphill bicycle ride to get home, too. 😛 So I know what you mean about the weather affecting things.
I got a tube of AS3 and used it on my Duron in place of AS2 recently. The CPU now runs 2-3C cooler, relative to the mobo temperature (as measured by an insensitive socket thermistor), so I think it is definitely effective... that probably translates into a 4-8C drop in actual core temp.
Now I really want some of those YS Tech fans myself, after reading your remarks about them 😀