diff --git a/spec/plainmonthday.html b/spec/plainmonthday.html
index fb42af389..f9cb40036 100644
--- a/spec/plainmonthday.html
+++ b/spec/plainmonthday.html
@@ -307,12 +307,12 @@ <h1>
         1. Set _calendar_ to ? CanonicalizeCalendar(_calendar_).
         1. Let _resolvedOptions_ be ? GetOptionsObject(_options_).
         1. Perform ? GetTemporalOverflowOption(_resolvedOptions_).
-        1. If _result_.[[Year]] is ~empty~, then
-          1. Assert: _calendar_ is *"iso8601"*.
+        1. If _calendar_ is *"iso8601"*, then
           1. Let _referenceISOYear_ be 1972 (the first ISO 8601 leap year after the epoch).
           1. Let _isoDate_ be CreateISODateRecord(_referenceISOYear_, _result_.[[Month]], _result_.[[Day]]).
           1. Return ! CreateTemporalMonthDay(_isoDate_, _calendar_).
         1. Let _isoDate_ be CreateISODateRecord(_result_.[[Year]], _result_.[[Month]], _result_.[[Day]]).
+        1. If ISODateWithinLimits(_isoDate_) is *false*, throw a *RangeError* exception.
         1. Set _result_ to ISODateToFields(_calendar_, _isoDate_, ~month-day~).
         1. NOTE: The following operation is called with ~constrain~ regardless of the value of _overflow_, in order for the calendar to store a canonical value in the [[Year]] field of the [[ISODate]] internal slot of the result.
         1. Set _isoDate_ to ? CalendarMonthDayFromFields(_calendar_, _result_, ~constrain~).
diff --git a/spec/plainyearmonth.html b/spec/plainyearmonth.html
index 323d55261..41c3da74f 100644
--- a/spec/plainyearmonth.html
+++ b/spec/plainyearmonth.html
@@ -477,10 +477,11 @@ <h1>
         1. Let _calendar_ be _result_.[[Calendar]].
         1. If _calendar_ is ~empty~, set _calendar_ to *"iso8601"*.
         1. Set _calendar_ to ? CanonicalizeCalendar(_calendar_).
-        1. Let _isoDate_ be CreateISODateRecord(_result_.[[Year]], _result_.[[Month]], _result_.[[Day]]).
-        1. Set _result_ to ISODateToFields(_calendar_, _isoDate_, ~year-month~).
         1. Let _resolvedOptions_ be ? GetOptionsObject(_options_).
         1. Perform ? GetTemporalOverflowOption(_resolvedOptions_).
+        1. Let _isoDate_ be CreateISODateRecord(_result_.[[Year]], _result_.[[Month]], _result_.[[Day]]).
+        1. If ISOYearMonthWithinLimits(_isoDate_) is *false*, throw a *RangeError* exception.
+        1. Set _result_ to ISODateToFields(_calendar_, _isoDate_, ~year-month~).
         1. NOTE: The following operation is called with ~constrain~ regardless of the value of _overflow_, in order for the calendar to store a canonical value in the [[Day]] field of the [[ISODate]] internal slot of the result.
         1. Set _isoDate_ to ? CalendarYearMonthFromFields(_calendar_, _result_, ~constrain~).
         1. Return ! CreateTemporalYearMonth(_isoDate_, _calendar_).