diff --git a/content/v2.0/reference/flux/functions/built-in/transformations/range.md b/content/v2.0/reference/flux/functions/built-in/transformations/range.md
index 934417faa..13b33b2dd 100644
--- a/content/v2.0/reference/flux/functions/built-in/transformations/range.md
+++ b/content/v2.0/reference/flux/functions/built-in/transformations/range.md
@@ -43,6 +43,11 @@ Absolute stop times are defined using timestamps.
 
 _**Data type:** Duration or Timestamp_
 
+{{% note %}}
+Flux only honors [RFC3339 timestamps](/v2.0/reference/flux/language/types#timestamp-format)
+and ignores dates and times provided in other formats. 
+{{% /note %}}
+
 ## Examples
 
 ###### Time range relative to now
diff --git a/content/v2.0/reference/flux/language/types.md b/content/v2.0/reference/flux/language/types.md
index eab5b72ae..4e33dbe62 100644
--- a/content/v2.0/reference/flux/language/types.md
+++ b/content/v2.0/reference/flux/language/types.md
@@ -44,6 +44,13 @@ float   the set of all IEEE-754 64-bit floating-point numbers
 A _time type_ represents a single point in time with nanosecond precision.
 The time type name is `time`.
 
+### Timestamp format
+Flux supports [RFC3339](https://tools.ietf.org/html/rfc3339#section-5.6) timestamps:
+
+- `YYYY-MM-DD`
+- `YYYY-MM-DDT00:00:00Z`
+- `YYYY-MM-DDT00:00:00.000Z`
+
 ## Duration types
 
 A _duration type_ represents a length of time with nanosecond precision.