diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index eacab181..73a03424 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -16,7 +16,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, windows-latest]
-        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13", "3.14"]
+        python-version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
         run-type: [std]
         test-path: ["."]
         include:
diff --git a/etc/environment.yml b/etc/environment.yml
index e5ad5e8e..020ea5e9 100644
--- a/etc/environment.yml
+++ b/etc/environment.yml
@@ -4,7 +4,7 @@ channels:
   - nodefaults
 dependencies:
   # required
-  - python >= 3.9
+  - python >= 3.10
   - libopenblas < 0.3.30
   - numpy
   - pandas
diff --git a/pyproject.toml b/pyproject.toml
index b5c33810..ad51d657 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -23,7 +23,7 @@ classifiers = [
     "Programming Language :: Python :: 3 :: Only",
     "Topic :: Scientific/Engineering :: Hydrology",
 ]
-requires-python = ">=3.9"
+requires-python = ">=3.10"
 dependencies = [
     "numpy",
     "pandas",