diff --git a/.github/workflows/ci_docs.yml b/.github/workflows/ci_docs.yml
index 4f886a67b69..ae16cdad084 100644
--- a/.github/workflows/ci_docs.yml
+++ b/.github/workflows/ci_docs.yml
@@ -74,6 +74,10 @@ jobs:
           # fetch all history so that setuptools-scm works
           fetch-depth: 0
 
+      - name: Get current week number of year
+        id: date
+        run: echo "date=$(date +%Y-W%W)" >> $GITHUB_OUTPUT  # e.g., 2024-W19
+
       # Install Micromamba with conda-forge dependencies
       - name: Setup Micromamba
         uses: mamba-org/setup-micromamba@v1.8.1
@@ -85,6 +89,8 @@ jobs:
               - nodefaults
           cache-downloads: false
           cache-environment: true
+          # environment cache is persistent for one week.
+          cache-environment-key: micromamba-environment-${{ steps.date.outputs.date }}
           create-args: >-
             python=3.12
             gmt=6.5.0
diff --git a/.github/workflows/ci_tests.yaml b/.github/workflows/ci_tests.yaml
index 5c6ec2c948e..edced909a0f 100644
--- a/.github/workflows/ci_tests.yaml
+++ b/.github/workflows/ci_tests.yaml
@@ -99,6 +99,10 @@ jobs:
           # fetch all history so that setuptools-scm works
           fetch-depth: 0
 
+      - name: Get current week number of year
+        id: date
+        run: echo "date=$(date +%Y-W%W)" >> $GITHUB_OUTPUT  # e.g., 2024-W19
+
       # Install Micromamba with conda-forge dependencies
       - name: Setup Micromamba
         uses: mamba-org/setup-micromamba@v1.8.1
@@ -110,6 +114,8 @@ jobs:
               - nodefaults
           cache-downloads: false
           cache-environment: true
+          # environment cache is persistent for one week.
+          cache-environment-key: micromamba-environment-${{ steps.date.outputs.date }}
           create-args: >-
             python=${{ matrix.python-version }}${{ matrix.optional-packages }}
             gmt=6.5.0
diff --git a/.github/workflows/ci_tests_dev.yaml b/.github/workflows/ci_tests_dev.yaml
index 020e08ec958..f7505109348 100644
--- a/.github/workflows/ci_tests_dev.yaml
+++ b/.github/workflows/ci_tests_dev.yaml
@@ -52,6 +52,10 @@ jobs:
           # fetch all history so that setuptools-scm works
           fetch-depth: 0
 
+      - name: Get current week number of year
+        id: date
+        run: echo "date=$(date +%Y-W%W)" >> $GITHUB_OUTPUT  # e.g., 2024-W19
+
       # Install Micromamba with conda-forge dependencies
       - name: Setup Micromamba
         uses: mamba-org/setup-micromamba@v1.8.1
@@ -63,6 +67,8 @@ jobs:
               - nodefaults
           cache-downloads: false
           cache-environment: true
+          # environment cache is persistent for one week.
+          cache-environment-key: micromamba-environment-${{ steps.date.outputs.date }}
           create-args: >-
             python=3.12
             cmake
diff --git a/.github/workflows/ci_tests_legacy.yaml b/.github/workflows/ci_tests_legacy.yaml
index a2d6357ef1c..8e857e24d24 100644
--- a/.github/workflows/ci_tests_legacy.yaml
+++ b/.github/workflows/ci_tests_legacy.yaml
@@ -58,8 +58,6 @@ jobs:
             channels:
               - conda-forge
               - nodefaults
-          cache-downloads: false
-          cache-environment: true
           create-args: >-
             python=3.10
             gmt=${{ matrix.gmt_version }}