diff --git a/README.rst b/README.rst
index 1a5715e..5021c16 100644
--- a/README.rst
+++ b/README.rst
@@ -38,8 +38,8 @@ Install
 Requirements
 ------------
 
-- Python 2.7 minimum
-- pip install numpy shapely
+- Python 2.7+
+- pip install numpy shapely six
 - pip install metpy enum34 - to run Jupyter Notebook examples
 
 Documentation