diff --git a/python/nwm_client_new/pyproject.toml b/python/nwm_client_new/pyproject.toml
index 9ea48bbf..48219755 100644
--- a/python/nwm_client_new/pyproject.toml
+++ b/python/nwm_client_new/pyproject.toml
@@ -22,6 +22,7 @@ classifiers = [
     "Operating System :: OS Independent",
 ]
 dependencies = [
+    "numpy>=1.20.0, <2; python<'3.10'",
     "numpy>=1.20.0",
     "pandas",
     "xarray",