I can only agree with Moonwalker, especially regards the latter point abut the launch control decisions. If you think predicting the weather is easy then you are sadly mistaken. Even with radar, airborne obs and a weather team watching the sky it's still not easy to give a cast iron prediction of conditions, especially when so many factors have to line up. Doubly more so in Eastern Florida!!
Also consider what is happening here before you criticise the repeated launch attempts and hold-offs. This is an unmanned test flight, which it is important to launch correctly and into safe atmospheric conditions, BUT it's unmanned and isn't scheduled for any particular orbit pattern. That means they keep trying until the window closes on them. If it'd have been a Shuttle launch it'd have scrubbed once and that'd have been it until tomorrow.
Also, put yourself in the shoes of the members of the launch control teams before you criticise them. This was a unique instance where they had to think on their feet and retry stuff as quickly as they could to get a launch in weather windows. You can't expect people to magic a weather prediction out of nowhere, they need facts and data to make an informed prediction. Personally I think 20 secs to do a weather prediction based on radar and aerial obs reports alone is pretty impressive. Hey, these people are only human, they are bound to um and err a bit, especially as it wasn't an emergency or a time critical launch (other than the weather).
I know it was a little frustrating compared to a STS launch, which seems to well orchestrated, but it all gets a bit seat of the pants when you are doing stuff like this on the fly, trying again and again to get a window of opportunity to launch. I'm pretty sure if they did anything like this in the 50s and 60s it was probably even more confused than this was, if only because they didn't have 50 years of practice behind them!
Give em a break, eh?