diff --git a/ci/setup_env.sh b/ci/setup_env.sh
index 78951c9def7cb..c36422884f2ec 100755
--- a/ci/setup_env.sh
+++ b/ci/setup_env.sh
@@ -108,6 +108,12 @@ fi
 echo "activate pandas-dev"
 source activate pandas-dev
 
+# Explicitly set an environment variable indicating that this is pandas' CI environment.
+#
+# This allows us to enable things like -Werror that shouldn't be activated in
+# downstream CI jobs that may also build pandas from source.
+export PANDAS_CI=1
+
 echo
 echo "remove any installed pandas package"
 echo "w/o removing anything else"
diff --git a/doc/source/whatsnew/v1.1.5.rst b/doc/source/whatsnew/v1.1.5.rst
index 29b0e99a3a356..552c8ced6b08a 100644
--- a/doc/source/whatsnew/v1.1.5.rst
+++ b/doc/source/whatsnew/v1.1.5.rst
@@ -33,6 +33,14 @@ Bug fixes
 
 .. ---------------------------------------------------------------------------
 
+.. _whatsnew_115.other:
+
+Other
+~~~~~
+- Only set ``-Werror`` as a compiler flag in the CI jobs (:issue:`33315`, :issue:`33314`)
+
+.. ---------------------------------------------------------------------------
+
 .. _whatsnew_115.contributors:
 
 Contributors
diff --git a/setup.py b/setup.py
index 9f33c045df6ed..0b1007794bbdb 100755
--- a/setup.py
+++ b/setup.py
@@ -409,15 +409,16 @@ def run(self):
     endian_macro = [("__LITTLE_ENDIAN__", "1")]
 
 
+extra_compile_args = []
+extra_link_args = []
 if is_platform_windows():
-    extra_compile_args = []
-    extra_link_args = []
     if debugging_symbols_requested:
         extra_compile_args.append("/Z7")
         extra_link_args.append("/DEBUG")
 else:
-    extra_compile_args = ["-Werror"]
-    extra_link_args = []
+    # PANDAS_CI=1 is set by ci/setup_env.sh
+    if os.environ.get("PANDAS_CI", "0") == "1":
+        extra_compile_args.append("-Werror")
     if debugging_symbols_requested:
         extra_compile_args.append("-g")