No, it's not. Nowadays we know how to predict the weather with great confidence. Prompting may get you different results each time. Moreover, LLMs depend on the context of your prompts (because of their memory), so a single prompt may be close to useless and two different people can get vastly different results.
> we know how to predict the weather with great confidence
some weather, sometimes. we're not good at predicting exact paths of tornadoes.
> so a single prompt may be close to useless and two different people can get vastly different results
of course, but it can be wrong 50% of the time or 5% of the time or .5% of the time and each of those thresholds unlock possibilities.