diff --git a/doc/manual/source/the-model-file.rst b/doc/manual/source/the-model-file.rst
index a1bb5afb5759c0eb78d7e0ca3bafa3f94f33b9ce..3685484cffb8763039ddd3b9c604c44e5abf5faa 100644
--- a/doc/manual/source/the-model-file.rst
+++ b/doc/manual/source/the-model-file.rst
@@ -98,7 +98,10 @@ observed:
   system; it is necessary to put it between quotes when specifying the
   extension or if the filename contains a non-alphanumeric character;
 * QUOTED_STRING indicates an arbitrary string enclosed between (single)
-  quotes.
+  quotes;
+* DATE indicates a time period which can be either a year (e.g. `2024Y` or
+  `2024A`), a half-year (`2024S1` or `2024H1`), a quarter (`2024Q2`) or a month
+  (`2024M3`) (see :ref:`dates in a mod file`).
 
 
 .. _var-decl: