Thanks to modern paints that adhere to surfaces like vinyl siding, you can alter its color, but the question remains: can you paint vinyl siding darker than it was made? The answer is no, and there's a very simple reason why this is the case.
Never Go Darker
Vinyl siding soaks up warmth from the sun. Too much heat absorbed by it can cause it to warp beyond repair. This is why vinyl siding is produced in lighter color shades, whether blue, brown, gray, green, etc. Were you to paint the siding darker than its original color, it would absorb more heat and be prone to warping.