diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index db8a760e..678aa25a 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -13,7 +13,7 @@ jobs:
             numpy-version: '1.22'
       fail-fast: false
     env:
-      COVERAGE_CORE: sysmon # Enable experimental faster sys.monitoring coverage for Python 3.12
+      COVERAGE_CORE: sysmon #
     steps:
       - uses: actions/checkout@v2
       - uses: actions/setup-python@v2
@@ -31,6 +31,10 @@ jobs:
           else
               python -m pip install --upgrade numpy==${{ matrix.numpy-version }}.*
           fi
+      # Enable experimental faster sys.monitoring coverage for Python 3.12
+      - name: Set COVERAGE_CORE=sysmon
+        run: echo COVERAGE_CORE=sysmon" >> $GITHUB_ENV
+        if: matrix.python-version == 3.12
       - name: Run Tests
         run: |
           set -x