A forecast drawn from the look of the sky is an informed guess, not a certainty. With patient study it improves your understanding and will sometimes warn you of a coming storm, but it does not make you an instant expert.
What the clouds look like right now carries clues to what the weather will do next. Learning to match a cloud formation with what usually follows lets an outdoor observer make their own forecast without formal training in meteorology.
People who depend on the weather outdoors tend to learn least about the wind, even though it shapes their day most directly. Watching for short-term wind changes fills that gap.