C++, 81 bytes
[](){for(time_t t=0,y;t<24;cout<<put_time(gmtime(&y),"%R %l:00%P\n"))y=t++*3600;}
This code requires using namespace std
somewhere preceding it.
It does a loop on the values 0...23. It multiplies each value by 3600, converts to a tm
struct and prints it. The print format %R
outputs the 24-hour and minute; the print formats %l
and %P
output the proper 12-hour parts; they require GNU.
A working online version is here.