diff --git a/.github/workflows/ci_workflows.yml b/.github/workflows/ci_workflows.yml
index a445844..383bfc4 100644
--- a/.github/workflows/ci_workflows.yml
+++ b/.github/workflows/ci_workflows.yml
@@ -37,12 +37,20 @@ jobs:
           pip install pytest pytest-cov>=4.0
           if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
 
-    - name: Get WebbPSF Data
+    - name: WebbPSF Data
       run: | # Get WebbPSF data files (just a subset of the full dataset!) and set up environment variable
            wget https://stsci.box.com/shared/static/0ojjfg3cieqdpd18vl1bjnpe63r82dx8.gz -O /tmp/minimal-webbpsf-data.tar.gz
            tar -xzvf /tmp/minimal-webbpsf-data.tar.gz
            echo "WEBBPSF_PATH=${{github.workspace}}/webbpsf-data" >> $GITHUB_ENV
 
+    - name: WebbPSF Extensions Data
+      run: | # Set up webbpsf_ext data environment variable
+           echo "WEBBPSF_EXT_PATH=${{github.workspace}}/webbpsf_ext_data" >> $GITHUB_ENV
+
+    - name: CDBS Data Path
+      run: | # Set up pycdbs environment variable
+           echo "PYSYN_CDBS=${{github.workspace}}/cdbs" >> $GITHUB_ENV
+
     - name: Check conda info
       run: conda info
 
diff --git a/webbpsf_ext/synphot_ext.py b/webbpsf_ext/synphot_ext.py
index 67a32de..3bea624 100644
--- a/webbpsf_ext/synphot_ext.py
+++ b/webbpsf_ext/synphot_ext.py
@@ -35,7 +35,13 @@ def download_cdbs_data(cdbs_path=None, verbose=False):
     if cdbs_path is None:
         cdbs_path = os.environ.get('PYSYN_CDBS', None)
         if cdbs_path is None:
-            raise ValueError("Environment variable PYSYN_CDBS is not set.")
+            # Set default path
+            cdbs_path = os.path.join(os.environ.get('WEBBPSF_EXT_PATH'), 'cdbs')
+            os.environ['PYSYN_CDBS'] = cdbs_path
+            cdbs_path = os.environ.get('PYSYN_CDBS', None)
+            if not os.path.exists(cdbs_path):
+                os.makedirs(cdbs_path, exist_ok=True)
+            # raise ValueError("Environment variable PYSYN_CDBS is not set.")
 
     # Download synphot data files
     res = download_data(cdbs_path, verbose=False)