[Django]-Django: Use of DATE_FORMAT, DATETIME_FORMAT, TIME_FORMAT in settings.py?

Searching through the source shows that DATETIME_FORMAT, etc., are only used when django.utils.formats.localize() is called, and that only seems to be called when django.template.VariableNodes are rendered.

I’m not sure when exactly VariableNodes are used in template rendering, but I would guess that if you have settings.USE_L10N turned on and you have a VariableNode, it will be localized.

localize looks like this:

def localize(value):
    """
    Checks if value is a localizable type (date, number...) and returns it
    formatted as a string using current locale format
    """
    if settings.USE_L10N:
        if isinstance(value, (decimal.Decimal, float, int)):
            return number_format(value)
        elif isinstance(value, datetime.datetime):
            return date_format(value, 'DATETIME_FORMAT')
        elif isinstance(value, datetime.date):
            return date_format(value)
        elif isinstance(value, datetime.time):
            return time_format(value, 'TIME_FORMAT')
    return value

To answer your question, I’d probably write a quick context processor that called localize() on everything in the context.

You can override DATE_FORMAT, DATETIME_FORMAT, TIME_FORMAT and other date/time formats when USE_L10N = True by creating custom format files as described in Django documentation.

In summary:

1. Set FORMAT_MODULE_PATH = 'yourproject.formats' in settings.py
2. Create directory structure yourproject/formats/en (replacing en with the corresponding ISO 639-1 locale code if you are using other locale than English) and add __init__.py files to all directories to make it a valid Python module
3. Add formats.py to the leaf directory, containing the format definitions you want to override, e.g. DATE_FORMAT = 'j. F Y'.

Example from an actual project here.

A late response, but hopefully this will help anyone else searching for this.
By setting USE_L10N = True in your settings, Django looks for locale specific formats, giving them precedence over non-locale related settings.

The solution: (to display 30/12/2017 on a DateField)

from django.conf.locale.en import formats as en_formats

en_formats.DATE_FORMAT = "%d/%m/%Y"

and for inputs (to accept 30/12/2017 or 30-12-2017)

en_formats.DATE_INPUT_FORMATS = ['%d/%m/%Y', '%d-%m-%Y']

Reference: https://mounirmesselmeni.github.io/2014/11/06/date-format-in-django-admin/

*tested on Django==1.10.7

You can partially format date and time but not entirely in a Django project according to my experiments with Django 4.2.1.

In Django Admin, set DATE_INPUT_FORMATS to format DateTimeField() and DateField() and set TIME_INPUT_FORMATS to format DateTimeField() and TimeField() in settings.py. *DATETIME_INPUT_FORMATS doesn’t work to any parts of a Django project and you can see my question explaining these 3 settings.

In Django Templates, set DATETIME_FORMAT, DATE_FORMAT and TIME_FORMAT to format DateTimeField(), DateField() and TimeField() respectively in settings.py and you can see my question explaining these 3 settings in addition to other 2 settings.

*You need to set USE_L10N False in settings.py to make these settings above work because USE_L10N is prior to them.