There is a new issue about the %z directive in strptime on the issue tracker: https://bugs.python.org/issue31800 (linked to a few related issues), and a linked PR expanding the definition of %z to match HH:MM: https://github.com/python/cpython/pull/4015 I think either adding a %:z directive or expanding the definition of %z would be pretty important, and I think there's a good case to be made for either one. To summarize the arguments for people on the mailing list: The argument for expanding the definition of %z that I find strongest is that according to the linux man pages ( http://man7.org/linux/man-pages/man3/strptime.3.html ), while %z generates +-HHMM in strftime, strptime is supposed to match "An RFC-822/ISO 8601 standard timezone specification",and ISO 8601 uses +-HH:MM, so if we're following those linux pages, we should be accepting the version with the colon. The argument that I find most compelling for adding a %:z directive are: 1. maintains the symmetry between strftime and strptime 2. allows users to be stricter about their datetime format 3. has precedent in that GNU's `date` command accepts %z, %:z and %::z formats Can we establish some consensus on which should be done so that it can be implemented? Best, Paul