[tedmiston]

A cursory glance at Django's timezone docs says pytz (which is optional but recommended) raises an exception when a time doesn't exist due to DST.

> Unfortunately, during DST transitions, some datetimes don’t exist or are ambiguous. In such situations, pytz raises an exception. Other tzinfo implementations, such as the local time zone used as a fallback when pytz isn’t installed, may raise an exception or return inaccurate results. That’s why you should always create aware datetime objects when time zone support is enabled.

https://docs.djangoproject.com/en/1.10/topics/i18n/timezones...