未雨绸缪

未雨綢繆
wèiyǔchóumóu
  1. lit. before it rains, bind around with silk (idiom, from Book of Songs 诗经); fig. to plan ahead
  2. to prepare for a rainy day

CEDICT

  1. (figurative) to plan ahead; to prepare before it is too late; to take precautions
  2. to plan ahead; to prepare before it is too late; to take precautions

Wiktionary

鸱鴞在未下雨前，便已着手修补窝巢。语本《诗经．豳风．鸱鴞》：「迨天之未阴雨，彻彼桑土，绸缪牖户。」比喻事先预备，防患未然。《隋唐演义．第五二回》：「况我家虽有预备，积储几仓，亦当未雨绸缪，要防自己饥馑。」

重編國語辭典

在事情发生之前就做好准备

維基詞典

Entry Composition

1 未 wèi
  1. not yet
  2. did not
  3. have not
  4. not
  5. 8th earthly branch: 1-3 p.m., 6th solar month (7th July-6th August), year of the Sheep
  6. ancient Chinese compass point: 210°
2 雨 yǔ rain

classifiers: 陣, 場
3 绸缪 chóumóu to be sentimentally attached to sb or sth