The city temperatures have returned from record low to normal, allowing the citizens to enjoy the outdoors again.

上面的内容摘自2022年高考英语天津卷（第二次）的单项填空。

查词典，record low 的意思是“有记录以来的最低点”“历史最低点”，此时的 low 是名词，不是形容词，而且是可数名词。这里为什么不用冠词呢？词典上好像都用的是 a record low。如：

Prices are at an all-time / record low. 价格已处于空前/有记录以来的最低点。

The currency slumped to a record low. 币值跌到了历史低点。

The temperature in Boston reached a record low last night. 昨晚波士顿的气温创下有记录以来的新低。

The nation’s infant mortality rate has reached a record low. 该国的婴儿死亡率已降至历史最低水平。