diff --git a/include/etl/private/chrono/month.h b/include/etl/private/chrono/month.h
index 10316f837..fdf4153f3 100644
--- a/include/etl/private/chrono/month.h
+++ b/include/etl/private/chrono/month.h
@@ -187,6 +187,14 @@ namespace etl
 
     private:
 
+      //***********************************************************************
+      /// Normalise to a in-range month
+      //***********************************************************************
+      ETL_NODISCARD ETL_CONSTEXPR void normalise()
+      {
+        value = ((value % 12U) == 0U) ? 12U : value;
+      }
+
       unsigned char value;
     };
 
diff --git a/include/etl/private/chrono/weekday.h b/include/etl/private/chrono/weekday.h
index fa520737e..03c973377 100644
--- a/include/etl/private/chrono/weekday.h
+++ b/include/etl/private/chrono/weekday.h
@@ -209,8 +209,24 @@ namespace etl
       //  std::chrono::weekday_last();
       //}
 
+      //***********************************************************************
+      /// Returns <b>true</b> if the day is a weekend.
+      //***********************************************************************
+      ETL_NODISCARD ETL_CONSTEXPR14 bool is_weekend()
+      {
+        return (c_encoding() == 0U) || (c_encoding() == 6U);
+      }
+
     private:
 
+      //***********************************************************************
+      /// Normalise to a in-range weekday
+      //***********************************************************************
+      ETL_NODISCARD ETL_CONSTEXPR void normalise()
+      {
+        value %= 7U;
+      }
+
       unsigned char value;
     };