The designation of time as "12:01am" being a clearer denotation of midnight compared to "12:00am" is a matter of convention and clarity in timekeeping.
The term "midnight" refers to the exact moment when one day transitions to the next, marking the beginning of a new day. However, there is a potential ambiguity in using "12:00am" to represent this moment. The term "am" traditionally stands for "ante meridiem," meaning "before noon." So, strictly speaking, "12:00am" could be interpreted as referring to the time before midnight rather than the moment of midnight itself.
To avoid confusion and provide a clearer denotation, the use of "12:01am" has become more common. By specifying "12:01am," it explicitly indicates the first minute of the new day, leaving no room for ambiguity. It clearly distinguishes the moment immediately following the end of one day and the start of the next.
In contrast, some style guides and organizations might discourage or advise against using "12:00am" to represent midnight precisely because of its potential for confusion. The preference for "12:01am" as a clearer denotation helps ensure accurate communication and avoids misunderstandings in time-sensitive contexts.
It's important to note that there isn't a universally agreed-upon standard for denoting midnight, and different conventions may be followed in different regions or contexts. The use of "12:01am" as a clearer denotation is a widely accepted practice but not an absolute rule.