How do I configure AM/PM notation to be capitalised system-wide in macOS Sequoia?

Question

How do I configure AM/PM notation to be capitalised system-wide in macOS Sequoia?

On my Intel-based Mac running macOS Sonoma (14.7.4), I have the AM/PM notation capitalised.

I want the same on my Apple silicon Mac running macOS Sequoia (15.3.1). I don't just want it for the clock but system-wide. So, if I were to use List view in Finder, the Date Modified column should show 24 Feb 2025 at 1:40 PM.

I read online that it has something to do with using Terminal to configure some keys but the examples I have seen show for date and time format but nothing on capitalising AM/PM notation. Which is what I want.

MacBook Pro 16″, macOS 15.3

Posted on Feb 24, 2025 5:47 AM

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Answer 1

Feb 24, 2025 6:41 AM in response to Mitochondrion

I tried 12-hour time as a test (I prefer 24-hour time). With my region set to either Portugal, or United Kingdom, AM/PM is always capitalised. I have the language set to English (US), I did not try changing it to English, because it is inopportune to restart my mac at the moment. I am guessing that for some odd reason they may have changed the capitalisation for your region. If that is the case, you may want to report using feedback:

https://www.apple.com/feedback

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Answer 2

Feb 24, 2025 6:57 AM in response to VikingOSX

Would it be possible to run some Terminal commands on my Intel-based Mac to understand what values it used from reading certain keys? So that I could apply the same on my Apple silicon Mac.

I think my Intel Mac have the capitalised AM/PM notation because it was either shipped with macOS High Sierra or macOS Mojave and you could manually adjust the AM/PM and I suppose that settings persisted ever since.

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Answer 3

VikingOSX

Level 10

124,520 points

Feb 24, 2025 7:12 AM in response to Mitochondrion

There is no Terminal command to alter the default ante/post meridiem case settings for your locale.

Yes, the same command that I performed in the Terminal above results in a capitalized PM in macOS High Sierra on a 2011 Mac mini. However, what is past with Apple operating systems is certainly no guarantee of prolog in operating system revisions four years later. You are stuck with lowercase am/pm in Sonoma and later.

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Answer 4

VikingOSX

Level 10

124,520 points

Feb 24, 2025 6:29 AM in response to Mitochondrion

On my Sequoia v15.3.1 system, all of my Finder date/time stamps show capitalized ante/post meridiem (AM/PM) letters. Same in my Finder menu extras bar. Same in my System Settings > General > Date & Time panel. I am using the U.S. Apple time server. In System Settings > Control Center, I have the Time enabled to show AM/PM.

I am using U.S. English. I have not run any Terminal command to achieve this AM/PM capitalization.

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Answer 5

VikingOSX

Level 10

124,520 points

Feb 24, 2025 6:36 AM in response to dialabrain

You may have something there about the locale. The Royal Museum in Greenwich uses lowercase ante/post meridiem notation on their site. Seems if these acronyms were meant to be capitalized in the UK, that treatment would appear on that museum site.

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Answer 6

Feb 24, 2025 7:17 AM in response to Mitochondrion

I did some testings on the virtual machine, switching to various English-speaking countries and this is what I have found:

So, only UK and Australia have the AM/PM notation in lowercased. I wish there is a way to customise it even if it is correct for the designated region. There must be a Terminal command for it. In older macOS versions, you could customise it regardless of region.

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