how is a broken clock right twice a day

A broken clock is right twice a day because it is stopped at a specific time, and that time occurs twice in a 24-hour period—once in the morning and once in the evening. For example, if a clock is stuck at 2:30, it will show the correct time at 2:30 AM and 2:30 PM, making it "right" twice each day. This saying is often used as an idiom to mean that even something or someone that is usually unreliable or wrong can sometimes be correct by pure chance or accident. The phrase highlights that nobody is wrong all the time, and even sources of misinformation can occasionally provide correct information, though it does not imply consistent reliability. While the literal meaning applies primarily to analog clocks that have stopped moving, the idiomatic use is more general, signifying occasional correctness despite usual inaccuracy or failure.