diff --git a/src/hflow/statistics.py b/src/hflow/statistics.py
index 838c8be0..5ef8be5c 100644
--- a/src/hflow/statistics.py
+++ b/src/hflow/statistics.py
@@ -6,8 +6,12 @@
 from dataclasses import dataclass
 from itertools import pairwise
 
+import numpy as np
+
 
 def _finite_number(value: float, name: str) -> float:
+    if isinstance(value, np.generic):
+        value = value.item()
     if isinstance(value, bool) or not isinstance(value, (int, float)):
         raise ValueError(f"{name} must be a finite number")
     try:
diff --git a/tests/test_statistics.py b/tests/test_statistics.py
index 60f9e1d2..a26e8782 100644
--- a/tests/test_statistics.py
+++ b/tests/test_statistics.py
@@ -3,6 +3,7 @@
 import itertools
 import math
 
+import numpy as np
 import pytest
 
 from hflow import (
@@ -165,6 +166,19 @@ def test_mean_combines_tiny_contributions_before_rounding_to_smallest_float() ->
     assert distribution.mean == smallest_float
 
 
+def test_measurements_accept_finite_numpy_numeric_scalars() -> None:
+    observation = WeightedValue(np.float32(0.5), np.int64(30))
+    assert observation == WeightedValue(0.5, 30)
+
+
+@pytest.mark.parametrize("invalid_numpy_bool", [np.bool_(True), np.bool_(False)])
+def test_measurements_reject_numpy_booleans(invalid_numpy_bool: np.bool_) -> None:
+    with pytest.raises(ValueError, match="value must be a finite number"):
+        WeightedValue(invalid_numpy_bool, 1)  # ty: ignore[invalid-argument-type]
+    with pytest.raises(ValueError, match="weight must be a finite number"):
+        WeightedValue(1, invalid_numpy_bool)  # ty: ignore[invalid-argument-type]
+
+
 @pytest.mark.parametrize("invalid_value", [True, "1", None, math.inf, -math.inf, math.nan])
 def test_measurements_reject_nonfinite_or_nonnumeric_values(invalid_value: object) -> None:
     with pytest.raises(ValueError, match="value must be a finite number"):