Support for Python 3.14.0

[valeriupredoi]

Support for Python 3.14.0 that will be released October 7, 2025.
What's new in 3.14 https://docs.python.org/3.14/whatsnew/3.14.html

Issues

As of 20 October 2025:

• just Fiona is at odds, all else is now fixed: https://github.com/ESMValGroup/ESMValCore/actions/runs/18654737590/job/53180940262

At the moment, iris=3.14 is restricting to Python<3.14 too, expecting to have that relaxed with iris=3.14.1

Past issues

As of 8 October 2025, we have a number of non-supporting packages (the others do support Python 3.14):

• • dask >=2025 # github.com/Multimodel tests failing due to mishandling of fill/missing values #2503
• • dask-jobqueue
• • distributed
• • fiona
• • intake-esm
• • iris >=3.12.2 # issue with iris saver with delayed and dask==2025.4.0 SciTools/iris#6417
• • iris-esmf-regrid >=0.11.0
• • iris-grib >=0.20.0 # github.com/Latest iris-grib v0.20.0 conflicts with ncl and esmpy>=8.6.0 #2535
• • ncdata
• • shapely >=2.0.0

Fixed issues

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.49%. Comparing base (040486b) to head (c578248).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2850   +/-   ##
=======================================
  Coverage   95.49%   95.49%           
=======================================
  Files         261      261           
  Lines       15557    15557           
=======================================
  Hits        14856    14856           
  Misses        701      701           

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