diff --git a/pvlib/tools.py b/pvlib/tools.py
index ce92fbd681..a81306b60c 100644
--- a/pvlib/tools.py
+++ b/pvlib/tools.py
@@ -435,8 +435,10 @@ def _get_sample_intervals(times, win_length):
     )
 
     # determine if we can proceed
-    if (_pandas_infer_freq_BaseOffset_transition_handler(times)
-        and len(np.unique(deltas)) == 1):
+    if (  # infer wrapper is None if no freq is determined
+        _pandas_infer_freq_BaseOffset_transition_handler(times)
+        and len(np.unique(deltas)) == 1
+    ):
         sample_interval = times[1] - times[0]
         sample_interval = sample_interval.seconds / 60  # in minutes
         samples_per_window = int(win_length / sample_interval)
@@ -476,7 +478,7 @@ def _pandas_infer_freq_BaseOffset_transition_handler(times):
     [^1]: pandas PR GH#64679: https://github.com/pandas-dev/pandas/pull/64679
     [^2]: https://pandas.pydata.org/docs/reference/api/pandas.infer_freq.html
     [^3]: https://pandas.pydata.org/docs/reference/api/pandas.tseries.offsets.BaseOffset.html
-    """
+    """  # noqa: E501
     if Version(pd.__version__) < Version("3.1.0rc0"):
         return pd.infer_freq(times)
     with pd.option_context({'future.infer_freq_returns_offset': True}):
@@ -485,6 +487,7 @@ def _pandas_infer_freq_BaseOffset_transition_handler(times):
         # base_offset:=None if unable to infer
         return getattr(base_offset, "freqstr", None)
 
+
 def _degrees_to_index(degrees, coordinate):
     """Transform input degrees to an output index integer.
     Specify a degree value and either 'latitude' or 'longitude' to get
diff --git a/tests/test_solarposition.py b/tests/test_solarposition.py
index fc31094362..9ee1ad05ea 100644
--- a/tests/test_solarposition.py
+++ b/tests/test_solarposition.py
@@ -831,13 +831,16 @@ def test_sun_rise_set_transit_geometric(expected_rise_set_spa, golden_mst):
     test_transit = solarposition._times_to_hours_after_local_midnight(st)
     # convert expected SPA sunrise, sunset, transit to local datetime indices
     expected_sunrise = pd.DatetimeIndex(
-        expected_rise_set_spa["sunrise"].dt.tz_convert(None).to_numpy(), tz="UTC"
+        expected_rise_set_spa["sunrise"].dt.tz_convert(None).to_numpy(),
+        tz="UTC",
     ).tz_convert(golden_mst.tz)
     expected_sunset = pd.DatetimeIndex(
-        expected_rise_set_spa["sunset"].dt.tz_convert(None).to_numpy(), tz="UTC"
+        expected_rise_set_spa["sunset"].dt.tz_convert(None).to_numpy(),
+        tz="UTC",
     ).tz_convert(golden_mst.tz)
     expected_transit = pd.DatetimeIndex(
-        expected_rise_set_spa["transit"].dt.tz_convert(None).to_numpy(), tz="UTC"
+        expected_rise_set_spa["transit"].dt.tz_convert(None).to_numpy(),
+        tz="UTC",
     ).tz_convert(golden_mst.tz)
     # convert expected times to hours since midnight as arrays of floats
     expected_sunrise = solarposition._times_to_hours_after_local_midnight(