Add warning for bugged xarray version

Author: peanutfun

climada/hazard/forecast.py

@@ -25,6 +25,7 @@
 
 import numpy as np
 import xarray as xr
+from packaging.version import Version
 from scipy import sparse
 
 from climada.hazard.xarray import HazardXarrayReader
@@ -35,6 +36,19 @@
 
 LOGGER = logging.getLogger(__name__)
 
+XARRAY_TIMEDELTA_BUG_BEGIN = Version("2025.04.0")
+XARRAY_TIMEDELTA_BUG_END = Version("2025.07.0")
+
+
+def xarray_has_timedelta_bug() -> bool:
+    """Return True if xarray contains the timedelta bug
+
+    See https://docs.xarray.dev/en/stable/whats-new.html#id80
+    """
+    return (Version(xr.__version__) >= XARRAY_TIMEDELTA_BUG_BEGIN) and (
+        Version(xr.__version__) < XARRAY_TIMEDELTA_BUG_END
+    )
+
 
 class HazardForecast(Forecast, Hazard):
     """A hazard object with forecast information"""
@@ -417,6 +431,15 @@ def from_xarray_raster(
         :py:meth:`climada.hazard.base.Hazard.from_xarray_raster`
             Parent method documentation for standard hazard loading
         """
+        if xarray_has_timedelta_bug():
+            LOGGER.warning(
+                "xarray version %s contains a bug that prevents proper timedelta "
+                "parsing. Consider updating to version %s or later, or downgrading to "
+                "before version %s",
+                xr.__version__,
+                XARRAY_TIMEDELTA_BUG_END,
+                XARRAY_TIMEDELTA_BUG_BEGIN,
+            )
 
         # Open dataset if needed
         if isinstance(data, (pathlib.Path, str)):

climada/hazard/test/test_forecast.py

@@ -26,18 +26,15 @@
 import pandas as pd
 import pytest
 import xarray as xr
-from packaging.version import Version
 from scipy.sparse import csr_matrix
 
 from climada.hazard.base import Hazard
-from climada.hazard.forecast import HazardForecast
+from climada.hazard.forecast import HazardForecast, xarray_has_timedelta_bug
 from climada.hazard.test.test_base import hazard_kwargs
 
 # See https://docs.xarray.dev/en/stable/whats-new.html#id80
 xarray_leadtime = pytest.mark.skipif(
-    (Version(xr.__version__) < Version("2025.07.0"))
-    and (Version(xr.__version__) >= Version("2025.04.0")),
-    reason="xarray timedelta bug",
+    xarray_has_timedelta_bug(), reason="xarray timedelta bug"
 )