What idiom means to act while conditions are favourable?

There are a few idioms that mean to act while conditions are favorable, but some are more appropriate than others depending on the context. Here are a few options:

Strongest matches:

* Strike while the iron is hot: This is the most common idiom for acting when conditions are favorable. It emphasizes taking advantage of a temporary opportunity.

* Make hay while the sun shines: Similar to the above, this idiom stresses the importance of working hard during a good time.

Less strong matches:

* Seize the day: While it means living life to the fullest, it can also imply acting on opportunities when they present themselves.

* While the going is good: This is less of an idiom and more of a phrase, but it conveys the same meaning of taking advantage of a favorable situation.

The best idiom to use will depend on the specific situation and the tone you want to convey.