diff --git a/noxfile.py b/noxfile.py
index d3e7d025..e7a4bafe 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -20,6 +20,7 @@ def pre_commit(session: nox.Session) -> None:
 # Keep list in-sync with ci.yml/test-linux & pyproject.toml
 @nox.session(python=["pypy3.8", "3.8", "3.9", "3.10", "3.11", "3.12"])
 def tests(session: nox.Session) -> None:
+    session.env["PYTHONWARNDEFAULTENCODING"] = "1"
     session.install("Twisted", "coverage[toml]")
     posargs = list(session.posargs)
 
diff --git a/src/towncrier/newsfragments/561.misc.rst b/src/towncrier/newsfragments/561.misc.rst
new file mode 100644
index 00000000..bdb991a5
--- /dev/null
+++ b/src/towncrier/newsfragments/561.misc.rst
@@ -0,0 +1 @@
+Enable reporting of EncodingWarnings when running tests.