User blog comment:YowAnime/Weather Manipulation/@comment-108.83.222.210-20200815205727/@comment-108.83.222.210-20200818043924

She already poses a threat now if not a direct one to the Yonko. She is unlikely to ever be able to outfight them, but she can cause them a lot of trouble. Look at how she managed to use her knowledge of weather science to help them in Whole Cake for a rather obvious example. She managed to use that against Big Mom multiple times utilizing Zeus, one of the beings formed from Big Mom's very soul. Then she eventually managed to capture him. The scientists seemed only interested in using their knowledge for research purposes and not for combat. Sometimes the most indirect things such as the weather can affect the outcome of a battle for better or for worse. Nami and the Yonko (as well as Eneru and others) possessing the ability to control the weather means that they can use the vast powers of nature to their advantage and eliminate or reduce the possibility of an ugly turn of the weather affecting the battle. If I recall, Rodger's final battle with Shiki ended when the unpredictable weather took a turn for the worst (he probably would have won anyway in my opinion, but it is worth noting).