On Debian 13 GNOME how to set *Time format* *24-hour* on attached user selection screen?
Sep 25, 11:26pm
The screenshot is the GDM login/user-selection screen, and its top clock (Sep 26 12:53 AM) uses the system locale — there's no settings panel there. GDM's clock format is controlled by the system locale's LC_TIME, so you change it system-wide:
Pick a locale with 24-hour format, e.g. en_GB.UTF-8 (English with 24h) or fr_FR.UTF-8. Make sure it's generated:
bash
sudo dpkg-reconfigure locales # tick en_GB.UTF-8, then select your default
Edit /etc/default/locale and add (or change) the time locale:
text
LC_TIME="en_GB.UTF-8"
You can keep LANG="en_US.UTF-8" for everything else.
Restart GDM (or reboot):
bash
sudo systemctl restart gdm3
The login screen clock will now show Sep 26 00:53 instead of 12:53 AM.
For your desktop session (after login), GNOME's Settings → Date & Time only offers 24h via the "Time Format" toggle if your session locale supports it; alternatively run:
bash
gsettings set org.gnome.desktop.interface clock-format '24h'
That affects the top panel, not the GDM screen — for GDM, the LC_TIME method above is the way.
Sep 25, 11:26pm
This is a shared conversation and may include unverified content that doesn't reflect Mistral AI's views. It cannot be edited because it contains private files.