diff --git a/src/lib.rs b/src/lib.rs
index 44cd4a9bd4..2ac19027b1 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -129,18 +129,20 @@ mod macros;
 /// Tantivy uses [`time`](https://crates.io/crates/time) for dates.
 pub use time;
 
+use crate::time::format_description::well_known::Rfc3339;
 use crate::time::{OffsetDateTime, PrimitiveDateTime, UtcOffset};
 
 /// A date/time value with second precision.
 ///
-/// This timestamp does not carry any time zone information.
+/// This timestamp does not carry any explicit time zone information.
 /// Users are responsible for applying the provided conversion
-/// functions consistently.
+/// functions consistently. Internally the time zone is assumed
+/// to be UTC, which is also used implicitly for JSON serialization.
 ///
 /// All constructors and conversions are provided as explicit
 /// functions and not by implementing any `From`/`Into` traits
 /// to prevent unintended usage.
-#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
+#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
 pub struct DateTime {
     unix_timestamp: i64,
 }
@@ -200,6 +202,13 @@ impl DateTime {
     }
 }
 
+impl fmt::Debug for DateTime {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let utc_rfc3339 = self.to_utc().format(&Rfc3339).map_err(|_| fmt::Error)?;
+        f.write_str(&utc_rfc3339)
+    }
+}
+
 pub use crate::error::TantivyError;
 
 /// Tantivy result.
diff --git a/src/query/query_parser/query_parser.rs b/src/query/query_parser/query_parser.rs
index 2b4ba2d62a..55ed2d9431 100644
--- a/src/query/query_parser/query_parser.rs
+++ b/src/query/query_parser/query_parser.rs
@@ -1039,9 +1039,10 @@ mod test {
 
     #[test]
     fn test_json_field_possibly_a_date() {
+        // Subseconds are discarded
         test_parse_query_to_logical_ast_helper(
             r#"json.date:"2019-10-12T07:20:50.52Z""#,
-            r#"(Term(type=Json, field=14, path=date, vtype=Date, DateTime { unix_timestamp: 1570864850 }) "[(0, Term(type=Json, field=14, path=date, vtype=Str, "2019")), (1, Term(type=Json, field=14, path=date, vtype=Str, "10")), (2, Term(type=Json, field=14, path=date, vtype=Str, "12t07")), (3, Term(type=Json, field=14, path=date, vtype=Str, "20")), (4, Term(type=Json, field=14, path=date, vtype=Str, "50")), (5, Term(type=Json, field=14, path=date, vtype=Str, "52z"))]")"#,
+            r#"(Term(type=Json, field=14, path=date, vtype=Date, 2019-10-12T07:20:50Z) "[(0, Term(type=Json, field=14, path=date, vtype=Str, "2019")), (1, Term(type=Json, field=14, path=date, vtype=Str, "10")), (2, Term(type=Json, field=14, path=date, vtype=Str, "12t07")), (3, Term(type=Json, field=14, path=date, vtype=Str, "20")), (4, Term(type=Json, field=14, path=date, vtype=Str, "50")), (5, Term(type=Json, field=14, path=date, vtype=Str, "52z"))]")"#,
             true,
         );
     }
diff --git a/src/schema/field_type.rs b/src/schema/field_type.rs
index 7c6669ef3d..2a46ecf2db 100644
--- a/src/schema/field_type.rs
+++ b/src/schema/field_type.rs
@@ -361,10 +361,8 @@ mod tests {
         let doc_json = r#"{"date": "2019-10-12T07:20:50.52+02:00"}"#;
         let doc = schema.parse_document(doc_json).unwrap();
         let date = doc.get_first(date_field).unwrap();
-        assert_eq!(
-            format!("{:?}", date),
-            "Date(DateTime { unix_timestamp: 1570857650 })"
-        );
+        // Time zone is converted to UTC and subseconds are discarded
+        assert_eq!("Date(2019-10-12T05:20:50Z)", format!("{:?}", date));
     }
 
     #[test]