It doesn't look like rain, so much as a noise texture with a motion blur...Almost like a blue curtain.
Part of this is due to the background color (rain doesn't usually have such a blue environment), and the whitish shapes, in addition to the "too regular" noise.

Perhaps you could lightly erase parts of the "rain" at a reduced opacity with one of the "speckle" brush shapes to make the downpour look a bit more random.

Although the bevel and emboss (and the triangle) in the sky above the arches doesn't really make sense to me, I do like the design between the arches - it adds a touch of eeriness to the nicely desaturated temple and rain effect.