diff --git a/nix/build-all.py b/nix/build-all.py
index f5a326399b..8fb5e2d5e8 100644
--- a/nix/build-all.py
+++ b/nix/build-all.py
@@ -926,6 +926,12 @@ os.environ["CPPFLAGS"] = CXXFLAGS
 os.environ["CFLAGS"] = CFLAGS
 os.environ["LDFLAGS"] = LDFLAGS
 
+# Use colors in logs to make them more readable locally.
+# Output from compiler used by cmake.
+os.environ["CMAKE_COLOR_DIAGNOSTICS"] = "ON"
+# Output from cmake itself.
+os.environ["CLICOLOR_FORCE"] = "1"
+
 # Some dependencies need a more recent CMake version than most distros provide
 # @tfk: this is no longer needed
 # build_dependency(name="cmake-%s" % (CMAKE_VERSION,), mode="autoconf", build_tool_args=[], download_url="https://cmake.org/files/v%s" % (CMAKE_VERSION_2,), download_name="cmake-%s.tar.gz" % (CMAKE_VERSION,))