diff --git a/.github/workflows/cov.yml b/.github/workflows/cov.yml
index 4eee0536..2dd46003 100644
--- a/.github/workflows/cov.yml
+++ b/.github/workflows/cov.yml
@@ -29,7 +29,7 @@ jobs:
     - name: Fetch Boost superproject
       run: |
         cd ..
-        git clone -b $GITHUB_BASE_REF --depth 5 https://github.com/boostorg/boost.git
+        git clone -b "${GITHUB_BASE_REF:-$GITHUB_REF_NAME}" --depth 5 https://github.com/boostorg/boost.git
         cd boost
         mv -f $GITHUB_WORKSPACE/* libs/histogram
         git submodule update --init --depth 5 tools/build tools/boostdep
diff --git a/.github/workflows/doc.yml b/.github/workflows/doc.yml
index 092175b4..2ded1bca 100644
--- a/.github/workflows/doc.yml
+++ b/.github/workflows/doc.yml
@@ -41,7 +41,7 @@ jobs:
     - name: Fetch Boost superproject
       run: |
         cd ..
-        git clone -b $GITHUB_BASE_REF --depth 5 https://github.com/boostorg/boost.git
+        git clone -b "${GITHUB_BASE_REF:-$GITHUB_REF_NAME}" --depth 5 https://github.com/boostorg/boost.git
         cd boost
         mv -f $GITHUB_WORKSPACE/* libs/histogram
         git submodule update --init --depth 5 tools/build tools/boostdep tools/quickbook tools/boostbook
diff --git a/.github/workflows/slow.yml b/.github/workflows/slow.yml
index 93f9cdfa..f472f372 100644
--- a/.github/workflows/slow.yml
+++ b/.github/workflows/slow.yml
@@ -31,7 +31,7 @@ jobs:
     - name: Fetch Boost superproject
       run: |
         cd ..
-        git clone -b $GITHUB_BASE_REF --depth 5 https://github.com/boostorg/boost.git
+        git clone -b "${GITHUB_BASE_REF:-$GITHUB_REF_NAME}" --depth 5 https://github.com/boostorg/boost.git
         cd boost
         mv -f $GITHUB_WORKSPACE/* libs/histogram
         git submodule update --init --depth 5 tools/build tools/boostdep
@@ -55,7 +55,7 @@ jobs:
     - name: Fetch Boost superproject
       run: |
         cd ..
-        git clone -b $GITHUB_BASE_REF --depth 5 https://github.com/boostorg/boost.git
+        git clone -b "${GITHUB_BASE_REF:-$GITHUB_REF_NAME}" --depth 5 https://github.com/boostorg/boost.git
         cd boost
         mv -f $GITHUB_WORKSPACE/* libs/histogram
         git submodule update --init --depth 5 tools/build tools/boostdep
@@ -76,7 +76,7 @@ jobs:
     - name: Fetch Boost superproject
       run: |
         cd ..
-        git clone -b $GITHUB_BASE_REF --depth 5 https://github.com/boostorg/boost.git
+        git clone -b "${GITHUB_BASE_REF:-$GITHUB_REF_NAME}" --depth 5 https://github.com/boostorg/boost.git
         cd boost
         mv -f $GITHUB_WORKSPACE/* libs/histogram
         git submodule update --init --depth 5 tools/build tools/boostdep
diff --git a/.github/workflows/superproject_cmake.yml b/.github/workflows/superproject_cmake.yml
index 6651fb55..3f212e92 100644
--- a/.github/workflows/superproject_cmake.yml
+++ b/.github/workflows/superproject_cmake.yml
@@ -18,7 +18,7 @@ jobs:
     - name: Fetch Boost superproject
       run: |
         cd ..
-        git clone -b $GITHUB_BASE_REF --depth 5 https://github.com/boostorg/boost.git
+        git clone -b "${GITHUB_BASE_REF:-$GITHUB_REF_NAME}" --depth 5 https://github.com/boostorg/boost.git
         cd boost
         git submodule update --init --depth 5
         rm -rf libs/histogram/*