diff --git a/geomagio/api/ws/data.py b/geomagio/api/ws/data.py
index 47971b277fa5fc801622678cd2547c0dedba3e30..d2dfc6967e3e86c9fed1f72f0a724968620a5548 100644
--- a/geomagio/api/ws/data.py
+++ b/geomagio/api/ws/data.py
@@ -76,7 +76,7 @@ def get_data_query(
         " NOTE: when using 'iaga2002' output format, a maximum of 4 elements is allowed",
     ),
     sampling_period: Union[SamplingPeriod, float] = Query(
-        None,
+        SamplingPeriod.MINUTE,
         title="data rate",
         description="Interval in seconds between values.",
     ),