diff --git a/pyproject.toml b/pyproject.toml
index fee78f1..4de5f29 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -29,7 +29,7 @@ dev = [
     "pytest-cov>=7.1.0,<7.1.1",
     "tox>=4.60.0,<4.60.1",
     "flake8>=7.3.0,<8.0.0",
-    "types-python-dateutil>=2.9.0.20260518,<3.0.0",
+    "types-python-dateutil>=2.9.0.20260807,<3.0.0",
     "mypy>=2.3.1,<3.0.0",
 ]
 
diff --git a/test-requirements.txt b/test-requirements.txt
index 82f9fa7..7192696 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -2,5 +2,5 @@ pytest>=9.1.1,<9.1.2
 pytest-cov>=7.1.0,<7.1.1
 tox>=4.60.0,<4.60.1
 flake8>=7.3.0,<7.4.0
-types-python-dateutil>=2.9.0.20260518,<3.0.0
+types-python-dateutil>=2.9.0.20260807,<3.0.0
 mypy>=2.3.1,<2.4
diff --git a/uv.lock b/uv.lock
index 962f4d6..4f7e02d 100644
--- a/uv.lock
+++ b/uv.lock
@@ -786,7 +786,7 @@ dev = [
     { name = "pytest", specifier = ">=9.1.1,<9.1.2" },
     { name = "pytest-cov", specifier = ">=7.1.0,<7.1.1" },
     { name = "tox", specifier = ">=4.60.0,<4.60.1" },
-    { name = "types-python-dateutil", specifier = ">=2.9.0.20260518,<3.0.0" },
+    { name = "types-python-dateutil", specifier = ">=2.9.0.20260807,<3.0.0" },
 ]
 
 [[package]]
@@ -886,11 +886,11 @@ wheels = [
 
 [[package]]
 name = "types-python-dateutil"
-version = "2.9.0.20260518"
+version = "2.9.0.20260807"
 source = { registry = "https://pypi.org/simple" }
-sdist = { url = "https://files.pythonhosted.org/packages/8d/e8/c01bdf0d7c3659428c091fbd693177093639565bcbc86bc20098e6d37cc6/types_python_dateutil-2.9.0.20260518.tar.gz", hash = "sha256:51f02dc03b61c7f6a07df45797d4dfe8a1aa47f0b7db9ad89f6fd3a1a70e1b51", size = 17082, upload-time = "2026-05-18T06:05:24.508Z" }
+sdist = { url = "https://files.pythonhosted.org/packages/c8/4e/b3fa538f9cb38dfece0d6ccf6d3d0d925bdedb144fb9c8129dfc007cd003/types_python_dateutil-2.9.0.20260807.tar.gz", hash = "sha256:e0b8a90d464c8684c66b7b8e4556d9074afdddcc56ca45323f0987134f9e7034", size = 17618, upload-time = "2026-08-07T04:17:13.491Z" }
 wheels = [
-    { url = "https://files.pythonhosted.org/packages/36/22/169273273ca34e9ab0ae2f387ba72ed7e09faaaf834da01d6b89c2bea71a/types_python_dateutil-2.9.0.20260518-py3-none-any.whl", hash = "sha256:d6a9c5bd0de61460c8fdef8ab2b400f956a1a1075cce08d4e2b4434e478c50b8", size = 18431, upload-time = "2026-05-18T06:05:23.641Z" },
+    { url = "https://files.pythonhosted.org/packages/e4/5e/3715867caea2f4cea56ccb04c851cde23ed063449c3b004c7a047f20dd48/types_python_dateutil-2.9.0.20260807-py3-none-any.whl", hash = "sha256:54aa3707350ed7a9cc0776fd2f6739679d6967d11b40150985e81edcb86df4db", size = 18486, upload-time = "2026-08-07T04:17:12.504Z" },
 ]
 
 [[package]]