"Nine days of heavy rain" is a phrase that could be used to describe a period of time during which it has rained heavily for nine consecutive days.

The phrase "nine days of heavy rain" is not a fixed idiom or expression in Engpsh, but rather a way of describing a specific weather event. It could be used in a variety of contexts, such as in a news report or a conversation about the weather.

Here are a few examples of how the phrase "nine days of heavy rain" could be used in Engpsh, along with their Chinese translations:

"The forecast is calpng for nine days of heavy rain starting tomorrow." (预测明天开始有九天的大雨。)
"We've had nine days of heavy rain in a row, and it doesn't look pke it's going to let up anytime soon." (连续九天都下大雨了,看起来不会很快停止。)
"I hope the nine days of heavy rain we've been having don't cause any flooding." (希望这九天的大雨不会引发洪水。)