diff --git a/x-pack/plugins/lens/server/routes/existing_fields.ts b/x-pack/plugins/lens/server/routes/existing_fields.ts
index d3a79dc7d8bfc..3a57a77a97726 100644
--- a/x-pack/plugins/lens/server/routes/existing_fields.ts
+++ b/x-pack/plugins/lens/server/routes/existing_fields.ts
@@ -183,6 +183,7 @@ async function fetchIndexPatternStats({
           {
             range: {
               [timeFieldName]: {
+                format: 'strict_date_optional_time',
                 gte: fromDate,
                 lte: toDate,
               },