diff --git a/pyproject.toml b/pyproject.toml
index 9b6ae1e1..1ef9b0ca 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -23,7 +23,7 @@ dependencies = [
     # Windows (and minimal containers), so available_timezones()/ZoneInfo need
     # this for the raid-schedule timezone validation + live-window checks to
     # work cross-platform.
-    "tzdata>=2024.1",
+    "tzdata>=2026.3",
     # Observability
     "prometheus-client>=0.20.0",
     # Reference-data pipeline: parse MediaWiki wikitext from EQ2i for the
diff --git a/uv.lock b/uv.lock
index 5974e903..c228fc60 100644
--- a/uv.lock
+++ b/uv.lock
@@ -328,7 +328,7 @@ requires-dist = [
     { name = "python-dotenv", specifier = ">=1.0.0" },
     { name = "python-multipart", specifier = ">=0.0.9" },
     { name = "slowapi", specifier = ">=0.1.9" },
-    { name = "tzdata", specifier = ">=2024.1" },
+    { name = "tzdata", specifier = ">=2026.3" },
     { name = "uvicorn", extras = ["standard"], specifier = ">=0.51.0" },
 ]
 
@@ -1055,11 +1055,11 @@ wheels = [
 
 [[package]]
 name = "tzdata"
-version = "2026.2"
+version = "2026.3"
 source = { registry = "https://pypi.org/simple" }
-sdist = { url = "https://files.pythonhosted.org/packages/ba/19/1b9b0e29f30c6d35cb345486df41110984ea67ae69dddbc0e8a100999493/tzdata-2026.2.tar.gz", hash = "sha256:9173fde7d80d9018e02a662e168e5a2d04f87c41ea174b139fbef642eda62d10", size = 198254, upload-time = "2026-04-24T15:22:08.651Z" }
+sdist = { url = "https://files.pythonhosted.org/packages/92/ff/5a28bdfd8c3ebec42564ac7d0e54ca3db65044a9314a97f9564fa7a1e926/tzdata-2026.3.tar.gz", hash = "sha256:4a1518b8993086a7982523e071643f3c0e5f213e75b21318e78bcabfff9d1415", size = 198674, upload-time = "2026-07-10T08:50:37.887Z" }
 wheels = [
-    { url = "https://files.pythonhosted.org/packages/ce/e4/dccd7f47c4b64213ac01ef921a1337ee6e30e8c6466046018326977efd95/tzdata-2026.2-py2.py3-none-any.whl", hash = "sha256:bbe9af844f658da81a5f95019480da3a89415801f6cc966806612cc7169bffe7", size = 349321, upload-time = "2026-04-24T15:22:05.876Z" },
+    { url = "https://files.pythonhosted.org/packages/e5/6d/b53b99a9f2766d095985947a5782f1702cabb129a34f7a802d7197af832f/tzdata-2026.3-py2.py3-none-any.whl", hash = "sha256:dc096730c87af6cab1b171c9d532be840741ff5d459015e7f6947bd7d7e54931", size = 348168, upload-time = "2026-07-10T08:50:36.46Z" },
 ]
 
 [[package]]