PyPI · #2171 most downloaded on PyPI

cftime

1.6.63.4M downloads/moUnidata/cftime ↗New releases in your daily digest, changelog included.

Time-handling functionality from netcdf4-python

Last release 6 days ago
28 Sep 2026
Release timing varies
gaps range from 5 weeks to 13 months
Most releases are documented
notes for 24 of 34 stable releases
Nothing withdrawn
no release was ever pulled
8 years old
37 releases · first in 2018

Release timeline

37 releases since 2018

2018202020222024

Releases

1.6.628 Sept 20262 sources agree
added new CF calendar "tai", which is the same as proleptic_gregorian but is only valid for dates after 1958-01-01.
added new CF calendar "tai", which is the same as proleptic_gregorian but is only valid for dates after 1958-01-01.
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version 1.6.6 release Latest

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1.6.513 Oct 20252 sources agree
python 3.14 wheels, 3.8/3.9 support dropped.
python 3.14 wheels, 3.8/3.9 support dropped.

roundtrip not correct when dates are all python datetime instances and calendar not proleptic_gregorian (issue #354).

fix cftime.datetime.strftime so it works with two digit year formatting (%y, issue #362).

speed up comparisions (using richcmp_) and update docs. Issue #365.

1.6.46 Jun 20242 sources agree

build aarch64 linux wheels (issue #333).

build aarch64 linux wheels (issue #333).
build musllinux wheels (issue #307).
return empty array if one provided to date2num (issue #315).
numpy 2.0 compatibility (issue #325).
handle nan/inf in num2date (issue #328).

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version 1.6.4 release

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1.6.319 Oct 20232 sources agree

add support for formats without separators in strptime (e.g. '20200229', issue #301). This required removing support for > 4 digit years.

add support for formats without separators in strptime (e.g. '20200229', issue #301). This required removing support for > 4 digit years.
set the c_api_binop_methods compiler directive to True to retain Cython 0.x behavior for arithmetic operators for Cython >= 3.0.0 (issue #271).
support for python 3.12.

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version 1.6.3 release

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1.6.218 Sept 20222 sources agree

num2date should not fail on an empty integer array (issue #287).

num2date should not fail on an empty integer array (issue #287).
longdouble keyword in date2num so that a roundtrip from a time to a date and back again does not lose microsecond precision when the units require the times be encoded as floating point values (PR #284)
added strptime method (issue #277).
cibuildwheel wheel-building workflow added to github actions by @ocefpaf (triggers binary wheel builds and uploads to pypi automatically when GH release created). PR #290.

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version 1.6.2 release

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1.6.130 Jun 20222 sources agree

fix failing tests on windows with numpy 1.23.0 (issue #278)

fix failing tests on windows with numpy 1.23.0 (issue #278)
expose to_tuple module function in public API.

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version 1.6.1 release

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1.5.222 Jan 2022Deprecated2 sources agree

silently change calendar='gregorian' to 'standard' internally, since 'gregorian' deprecated in CF v1.9 (issue #256).

silently change calendar='gregorian' to 'standard' internally, since 'gregorian' deprecated in CF v1.9 (issue #256).
add "is_leap_year" function (issue #259).
wheels that work on Apple M1 (arm64) available on pypi.

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1.5.124 Sept 20212 sources agree

added support for "common_year" and "common_years" units for "noleap" and "365_day" calendars (issue #5, PR #246)

added support for "common_year" and "common_years" units for "noleap" and "365_day" calendars (issue #5, PR #246)
check consistency of year arg and has_year_zero kwarg in cftime.datetime (issue #248). Also assume if has_year_zero not specified it should be True if year=0. Allow replace method to change has_year_zero. Issue UserWarning if year set to zero and calendar default is changed from False to True (so that user is aware the resulting instance will not be CF compliant).
'360_day' was missing from list of 'idealized' calendars.
fixed a bug that led to subclasses losing their type identity upon pickling (issue #251, PR #252).
Change default behavior of proleptic_gregorian to has_year_zero=T (to be consistent with ISO-8601 since CF does not specify the year zero convention for this calendar). Issue warning when trying to to create a cftime.datetime instance that is not allowed in CF (PR #238).

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version 1.5.1 release

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1.5.020 May 2021Deprecated2 sources agree

clean-up deprecated calendar specific subclasses (PR #231).

clean-up deprecated calendar specific subclasses (PR #231).
added string formatting support to cftime.datetime objects (via cftime.datetime.__format__) PR #232.
add support for astronomical year numbering (including year zero) for real-world calendars using 'has_year_zero' cftime.datetime kwarg (PR #234). Default is False for 'real-world' calendars ('julian', 'gregorian'/'standard', 'proleptic_gregorian'). Ignored for idealized calendars like '360_day (they always have year zero).
add "change_calendar" cftime.datetime method to switch to another 'real-world' calendar. Enable comparison of cftime.datetime instances with different 'real-world' calendars (using the new change_calendar method)
remove legacy utime class, and legacy JulianDayFromDate and DateFromJulianDay functions (replaced by cftime.datetime.toordinal and cftime.datetime.fromordinal). PR #235.
Change ValueError to TypeError in sub (issue #236, PR #236).

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version 1.5.0 release

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1.4.12 Feb 20212 sources agree

Restore use of calendar-specific sub-classes in cftime.num2date, cftime.datetime.__add__, and cftime.datetime.__sub__. The use of them will be removed

Restore use of calendar-specific sub-classes in cftime.num2date, cftime.datetime.__add__, and cftime.datetime.__sub__. The use of them will be removed in a later release.
add 'fromordinal' static method to create a cftime.datetime instance from a julian day ordinal and calendar (inverse of 'toordinal').

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1.4.031 Jan 20212 sources agree

cftime.date2num will now always return an array of integers, if the units and times allow. Previously this would only be true if the units were 'micro

cftime.date2num will now always return an array of integers, if the units and times allow. Previously this would only be true if the units were 'microseconds' (PR #225). In other circumstances, as before, cftime.date2num will return an array of floats.
Rewrite of julian day/calendar functions (_IntJulianDayToCalendar and _IntJulianDayFromCalendar) to remove GPL'ed code. cftime license changed to MIT (to be consistent with netcdf4-python).
Added datetime.toordinal() (returns julian day, kwarg 'fractional' can be used to include fractional day).
cftime.datetime no longer uses calendar-specific sub-classes.

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version 1.4.0 release

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1.3.117 Jan 20212 sources agree

fix for issue #211 (PR #212) bug in masked array handling in date2num)

fix for issue #211 (PR #212) bug in masked array handling in date2num)
switch from travis/appveyor to github actions for CI/CD (PR #215).
switch to cython language_level=3 (no more support for python 2) (PR #217).
add init.py to test dir so pytest coverage works again. Add Coveralls step to github actions workflow to upload coverage data to coveralls.io (PR #217).
move package under 'src' directory so cftime can be imported from install dir (PR #218 - see https://blog.ionelmc.ro/2014/05/25/python-packaging/#the-structure).

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version 1.3.1 release

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1.3.016 Nov 2020Deprecated2 sources agree

Fixes issue #198. The calendar specific sub-classes are now deprecated, but remain for now as stubs that just instantiate the base class and override…

zero pad years in strtime (issue #194)
have cftime.datetime constructor create 'calendar-aware' instances (default is 'standard' calendar, if calendar='' or None the instance is not calendar aware and some methods, like dayofwk, dayofyr, add and sub, will not work). Fixes issue #198. The calendar specific sub-classes are now deprecated, but remain for now as stubs that just instantiate the base class and override repr.
update regex in _cpdef _parse_date so reference years with more than four digits can be handled.
Change default calendar in cftime.date2num from 'standard' to None (calendar associated with first input datetime object is used).
add cftime.datetime.tzinfo=None for compatibility with python datetime (issue #208).

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version 1.3.0 release

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1.2.120 Jul 20202 sources agree

num2date uses 'proleptic_gregorian' scheme when basedate is post-Gregorian but date is pre-Gregorian (issue #182).

num2date uses 'proleptic_gregorian' scheme when basedate is post-Gregorian but date is pre-Gregorian (issue #182).
fix 1.2.0 regression (date2num no longer works with numpy scalar array inputs, issue #185).
Fix for issue #187 (have date2num round to the nearest second when within 1 microsecond).
Fix for issue #189 (leap years calculated incorrectly for negative years in proleptic_gregorian calendar).

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1.2.05 Jul 20202 sources agree

Return the default values of dayofwk and dayofyr when calendar is '' (issue #173).

Return the default values of dayofwk and dayofyr when calendar is '' (issue #173).
fix treatment of masked arrays in num2date and date2num (issue #175). Also make sure masked arrays are output from num2date/date2num if masked arrays are input.
Where possible, use timedelta arithmetic to decode times exactly within num2date (issue #171).
Make taking the difference between two cftime datetimes to produce a timedelta exact to the microsecond; depending on the units encoding, this enables date2num to be exact as well (issue #109).
utime.date2num/utime.num2date now just call module level functions. JulianDayFromDate/DateFromJulianDay no longer used internally (PR #180).

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1.1.013 Feb 20202 sources agree

improved exceptions for time differences (issue #128, PR #131).

improved exceptions for time differences (issue #128, PR #131).
fix intersphinx entries (issue #133, PR #133)
make only_use_cftime_datetimes=True by default, so cftime datetime instances are returned by default by num2date (instead of returning python datetime instances where possible). Issue #136, PR #135.
Add daysinmonth attribute (issue #137, PR #138).
If only_use_python_datetimes=True and only_use_cftime_datetimes=False, num2date only returns python datetime instances and raises an exception if this is not possible. num2pydate convenience function added which just calls num2date with only_use_python_datetimes=True and only_use_cftime_datetimes=False. Remove positive times check, raise ValueError if python datetime tries to compute a date before MINYEAR (issue #134, PR #139)
Fix for fractional seconds in reference date in units string (issue #140, PR # 141).

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