12.30 pm just after noon. 12.30 am is just after midnight. This makes sense, because the first is very early 'afternoon' while the second is very early morning. While we do tend to refer to midday as 12pm and midnight as 12am, strictly speaking this is illogical. The abbreviation 'am' stands for 'ante meridiem', which is a Latin term meaning 'before noon', while 'pm' stands for 'post meridiem' meaning 'after noon'. Therefore, both 12pm and 12am denote the same time of day : twelve hours after noon or twelve hours before noon are both midnight.

Just after noon. Noon is 12pm, midnight 12am.

It can be confusing because one would think 1pm would be the start of the afternoon and 1am would be the start of the morning. 1 o'clock to 12:59 should be all the same timezone right? Unfortunately that's not how it works. 12 o'clock is the beginning of a new timezone. After 11:59pm at night the clock ticks over to 12am which is now the morning. Similar to 11:59am in the morning becomes 12pm in the afternoon. I know it isn't 100% intuitive but just remember that any time that's AM is in the morning after 12 and any time that's PM is the afternoon after 12.