I'd say something smartassy like that too for most theories like this, but Locke clearly predicted the moment rain would fall once before, and Juliet seemed to indicate the same thing. I agree it has something to do with Dharma meteorology experiments.
Exactly. Nancy Drew has a point. Either the rain is on a cycle that the Others are aware of, or there is some kind of link with the Island that makes them more aware of weather patterns, or something like that, but it wasn't just coincidence or the smell of rain. (A) Why mention it at all? Why not just let it start raining. (B) No trickle of rain, no drops and then a gradual increase. One minute it's not raining, the next minute it's full on raining. Yeah, I know that can happen naturally, but I think it's foreshadowing that it happened the same way to Locke and Juliet. Also, I think it's much more telling that she predicting the rain within 45 seconds or so, just as Locke did, than predicting it a day or a few hours in advance. The timing is too coincidental.
I agree that we often make something out of nothing, but to me putting this down as coincidence is just ignoring the obvious.
The big question is, what tipped her off? Is it time based like Nancy said, a psychic link the Island like I think, or something else? I'm intrigued by Nancy's theory about a time cycle.