For historical reasons[0], with 12-hour clocks, 12 is generally treated as zero. A general fix for this is probably something like Linux locale settings. It's

For historical reasons[0], with 12-hour clocks, 12 is generally treated as zero. A general fix for this is probably something like Linux locale settings. It's going to be a rather flawed solution, what with those settings being super complicated. [0]- Lore is that the sundial and dividing the day into 12 sections happened before the invention of the number zero, but I don't know if this is accurate.