diff --git a/.github/workflows/nightly.yml b/.github/workflows/nightly.yml
index 3dba6f28f..2b33c45a8 100644
--- a/.github/workflows/nightly.yml
+++ b/.github/workflows/nightly.yml
@@ -93,7 +93,7 @@ jobs:
       - uses: actions/checkout@v1
       - uses: actions/setup-python@v2
         with:
-          python-version: '3.x'
+          python-version: '3.8.x'
 
       - name: Install B2 CLI
         shell: bash