diff --git a/doc/whats-new.rst b/doc/whats-new.rst
index 45273d31ca5..d075a9a590e 100644
--- a/doc/whats-new.rst
+++ b/doc/whats-new.rst
@@ -44,6 +44,7 @@ Bug fixes
   By `Deepak Cherian <https://github.com/dcherian>`_.
 - Fix groupby sum, prod for all-NaN groups with ``flox``. (:issue:`7808`).
   By `Deepak Cherian <https://github.com/dcherian>`_.
+- Use `numpy.can_cast` to avoid a RuntimeWarning from numpy. (:pull:`7834`).
 
 Documentation
 ~~~~~~~~~~~~~
diff --git a/xarray/coding/times.py b/xarray/coding/times.py
index 3745d61acc0..a746f26385a 100644
--- a/xarray/coding/times.py
+++ b/xarray/coding/times.py
@@ -615,9 +615,8 @@ def encode_datetime(d):
 
 
 def cast_to_int_if_safe(num) -> np.ndarray:
-    int_num = np.asarray(num, dtype=np.int64)
-    if (num == int_num).all():
-        num = int_num
+    if np.can_cast(num, to=np.int64, casting="safe"):
+        return np.asarray(num, dtype=np.int64)
     return num