雨夠了 “Rain Enough”
那國王傳旨道：「雨夠了，雨夠了；十分再多，又渰壞了禾苗，反為不美。」五鳳樓下聽事官策馬冒雨來報：「聖僧，雨夠了。」行者聞言，將金箍棒往上又一指。那国王传旨道：「雨够了，雨够了；十分再多，又渰坏了禾苗，反为不美。」五凤楼下听事官策马冒雨来报：「圣僧，雨够了。」行者闻言，将金箍棒往上又一指。
逐句解 Line by line
That king passed down a decree: “The rain is enough, the rain is enough;
那國王: 那 = nà. 傳旨 "to pass down a command."
any more, and it would drown the young crops, and turn to no good.”
渰壞了 (yǎn) "to flood and ruin." 禾苗 "the seedling grain," the young crop the elders came about. 反為不美: 為 = wéi, to become -- "would turn out badly instead." He is right, and it is the one genuinely competent thing he does all chapter.
Below the Five-Phoenix Tower, an attending officer spurred his horse through the rain to report, “Holy monk, the rain is enough.”
聽事官 "the officer in attendance." 策馬冒雨 "whipping his horse on through the rain," which is a nice detail: the messenger gets soaked delivering the news that there has been enough rain.
Pilgrim, hearing it, pointed the gold-banded cudgel up once again.
將金箍棒: 將 = jiāng. 往上又一指: 一 = yì.
The rain is not merely produced, it is regulated. The king calls a halt because any more would drown the seedlings, and Wukong turns it off with a point of the stick.
That is the real demonstration, and it is easy to read past. Anyone might get lucky with a storm. Starting one on cue, holding it for a morning, and stopping it the moment the crops have had enough is not luck, and the clearing that follows will put the matter beyond argument.