Preserve formatting of reference time units under pandas 2.0.0

doc/whats-new.rst

@@ -47,6 +47,12 @@ Bug fixes
   By `Thomas Coleman <https://github.com/ColemanTom>`_.
 - Proper plotting when passing :py:class:`~matplotlib.colors.BoundaryNorm` type argument in :py:meth:`DataArray.plot`. (:issue:`4061`, :issue:`7014`,:pull:`7553`)
   By `Jelmer Veenstra <https://github.com/veenstrajelmer>`_.
+- Ensure the formatting of time encoding reference dates outside the range of
+  nanosecond-precision datetimes remains the same under pandas version 2.0.0
+  (:issue:`7420`, :pull:`7441`).
+  By `Justus Magin <https://github.com/keewis>`_ and
+  `Spencer Clark  <https://github.com/spencerkclark>`_.
+
 
 Documentation
 ~~~~~~~~~~~~~

xarray/core/formatting.py

@@ -114,9 +114,9 @@ def calc_max_rows_last(max_rows: int) -> int:
 
 def format_timestamp(t):
     """Cast given object to a Timestamp and return a nicely formatted string"""
-    # Timestamp is only valid for 1678 to 2262
     try:
-        datetime_str = str(pd.Timestamp(t))
+        timestamp = pd.Timestamp(t)
+        datetime_str = timestamp.isoformat(sep=" ")
     except OutOfBoundsDatetime:
         datetime_str = str(t)