[New-bugs-announce] [issue4775] Incorrect documentation - UTC time

David Morley report at bugs.python.org
Tue Dec 30 03:17:22 CET 2008

New submission from David Morley <morley at ai.sri.com>:

There is a systemic error in the Python documentation on time (such as 
<http://docs.python.org/library/time.html>). The term UTC is used 
incorrectly in the documentation where the term UT1 should be used.

The difference is that UTC includes leap seconds, whereas UT1 does not (see <http://en.wikipedia.org/wiki/Coordinated_Universal_Time>). The 
conversion routines ignore leap seconds, e.g., (time.mktime((2000,1,1,12,0,0,0,0,0))-
time.mktime((1990,1,1,12,0,0,0,0,0))) returns an exact multiple of 
24*60*60 and does not include all the leap seconds added between those 
dates. Using UT1 is more sensible that using UTC, since with UTC it is 
impossible to know when future leap seconds will be added, and hence 
impossible to convert future times to a number of seconds past the 

assignee: georg.brandl
components: Documentation
messages: 78497
nosy: georg.brandl, luckmor
severity: normal
status: open
title: Incorrect documentation - UTC time
versions: Python 2.5

Python tracker <report at bugs.python.org>

More information about the New-bugs-announce mailing list