chǔ​rùn'ér​yǔ

small signs reveal big events

Senses

础润而雨/ 礎潤而雨 chǔ​rùn'ér​yǔ small signs reveal big events

Literally meaning that moisture on a stone pillar base predicts rain, this idiom describes how small signs can reveal the truth or the way things are going to develop.

References

synonym 础润而雨/礎潤而雨 月晕而风/月暈而風
see 月晕而风/月暈而風 础润而雨/礎潤而雨