If used the trial and had mixed results but I guess, just like the weather things change.
When I first got the trial it predicted a great sunset down on the coast not far from me. I wend down that morning to scout out the area and found a great composition. By late afternoon skyfire had changed its mind but I went down to the coast anyway. The sunset never materialised.
It has predicted colourful skys where I live a number of times and has been spot on.
I haven't signed up yet as I've been busy, but for £20/year, I'll give it a go.