diff --git a/include/chrono b/include/chrono
index 1b90757..06fa658 100644
--- a/include/chrono
+++ b/include/chrono
@@ -1810,7 +1810,7 @@
     unsigned char __wd;
 public:
   weekday() = default;
-  inline explicit constexpr weekday(unsigned __val) noexcept : __wd(static_cast<unsigned char>(__val)) {}
+  inline explicit constexpr weekday(unsigned __val) noexcept : __wd(static_cast<unsigned char>(__val == 7 ? 0 : __val)) {}
   inline constexpr          weekday(const sys_days& __sysd) noexcept
           : __wd(__weekday_from_days(__sysd.time_since_epoch().count())) {}
   inline explicit constexpr weekday(const local_days& __locd) noexcept
@@ -1822,7 +1822,8 @@
   inline constexpr weekday  operator--(int) noexcept { weekday __tmp = *this; --(*this); return __tmp; }
          constexpr weekday& operator+=(const days& __dd) noexcept;
          constexpr weekday& operator-=(const days& __dd) noexcept;
-  inline explicit constexpr operator unsigned() const noexcept { return __wd; }
+  inline constexpr unsigned c_encoding()   const noexcept { return __wd; }
+  inline constexpr unsigned iso_encoding() const noexcept { return __wd == 0u ? 7 : __wd; }
   inline constexpr bool ok() const noexcept { return __wd <= 6; }
          constexpr weekday_indexed operator[](unsigned __index) const noexcept;
          constexpr weekday_last    operator[](last_spec) const noexcept;
@@ -1842,7 +1843,7 @@
 
 inline constexpr
 bool operator==(const weekday& __lhs, const weekday& __rhs) noexcept
-{ return static_cast<unsigned>(__lhs) == static_cast<unsigned>(__rhs); }
+{ return __lhs.c_encoding() == __rhs.c_encoding(); }
 
 inline constexpr
 bool operator!=(const weekday& __lhs, const weekday& __rhs) noexcept
@@ -1850,7 +1851,7 @@
 
 inline constexpr
 bool operator< (const weekday& __lhs, const weekday& __rhs) noexcept
-{ return static_cast<unsigned>(__lhs) <  static_cast<unsigned>(__rhs); }
+{ return __lhs.c_encoding() < __rhs.c_encoding(); }
 
 inline constexpr
 bool operator> (const weekday& __lhs, const weekday& __rhs) noexcept
@@ -1866,7 +1867,7 @@
 
 constexpr weekday operator+(const weekday& __lhs, const days& __rhs) noexcept
 {
-    auto const __mu = static_cast<long long>(static_cast<unsigned>(__lhs)) + __rhs.count();
+    auto const __mu = static_cast<long long>(__lhs.c_encoding()) + __rhs.count();
     auto const __yr = (__mu >= 0 ? __mu : __mu - 6) / 7;
     return weekday{static_cast<unsigned>(__mu - __yr * 7)};
 }
@@ -1879,7 +1880,7 @@
 
 constexpr days operator-(const weekday& __lhs, const weekday& __rhs) noexcept
 {
-    const int __wdu = static_cast<unsigned>(__lhs) - static_cast<unsigned>(__rhs);
+    const int __wdu = __lhs.c_encoding() - __rhs.c_encoding();
     const int __wk = (__wdu >= 0 ? __wdu : __wdu-6) / 7;
     return days{__wdu - __wk * 7};
 }
diff --git a/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/weekday_last.pass.cpp b/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/weekday_last.pass.cpp
index 4ecf6d2..c4f7d3e 100644
--- a/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/weekday_last.pass.cpp
+++ b/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/weekday_last.pass.cpp
@@ -38,7 +38,7 @@
     for (unsigned i = 1; i <= 50; ++i)
     {
         month_weekday_last mdl(January, weekday_last{weekday{i}});
-        assert( static_cast<unsigned>(mdl.weekday_last().weekday()) == i);
+        assert( mdl.weekday_last().weekday().c_encoding() == (i == 7 ? 0 : i));
     }
 
   return 0;
diff --git a/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/weekday.pass.cpp b/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/weekday.pass.cpp
index e9c204d..002c336 100644
--- a/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/weekday.pass.cpp
+++ b/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/weekday.pass.cpp
@@ -33,7 +33,7 @@
     for (unsigned i = 0; i <= 6; ++i)
     {
         weekday_indexed wdi(weekday{i}, 2);
-        assert( static_cast<unsigned>(wdi.weekday()) == i);
+        assert( wdi.weekday().c_encoding() == i);
     }
 
   return 0;
diff --git a/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.members/ok.pass.cpp b/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.members/ok.pass.cpp
index eb0636a..1c04138 100644
--- a/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.members/ok.pass.cpp
+++ b/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.members/ok.pass.cpp
@@ -29,7 +29,7 @@
 
     static_assert( weekday_last{weekday{0}}.ok(), "");
     static_assert( weekday_last{weekday{1}}.ok(), "");
-    static_assert(!weekday_last{weekday{7}}.ok(), "");
+    static_assert(!weekday_last{weekday{8}}.ok(), "");
 
     for (unsigned i = 0; i <= 255; ++i)
         assert(weekday_last{weekday{i}}.ok() == weekday{i}.ok());
diff --git a/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/c_encoding.pass.cpp b/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/c_encoding.pass.cpp
new file mode 100644
index 0000000..b62c67e
--- /dev/null
+++ b/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/c_encoding.pass.cpp
@@ -0,0 +1,45 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+// UNSUPPORTED: c++98, c++03, c++11, c++14, c++17
+
+// <chrono>
+// class weekday;
+
+//  constexpr unsigned c_encoding() const noexcept;
+
+
+#include <chrono>
+#include <type_traits>
+#include <cassert>
+
+#include "test_macros.h"
+
+template <typename WD>
+constexpr bool testConstexpr()
+{
+    WD wd{5};
+    return wd.c_encoding() == 5;
+}
+
+int main(int, char**)
+{
+    using weekday = std::chrono::weekday;
+
+    ASSERT_NOEXCEPT(                    std::declval<weekday&>().c_encoding());
+    ASSERT_SAME_TYPE(unsigned, decltype(std::declval<weekday&>().c_encoding()));
+
+    static_assert(testConstexpr<weekday>(), "");
+
+    for (unsigned i = 0; i <= 10; ++i)
+    {
+        weekday wd(i);
+        assert(wd.c_encoding() == (i == 7 ? 0 : i));
+    }
+
+  return 0;
+}
diff --git a/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.local_days.pass.cpp b/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.local_days.pass.cpp
index 06656fb..3db7856 100644
--- a/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.local_days.pass.cpp
+++ b/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.local_days.pass.cpp
@@ -42,7 +42,7 @@
     constexpr weekday wd{sd};
 
     static_assert( wd.ok(), "");
-    static_assert(static_cast<unsigned>(wd) == 4, "");
+    static_assert( wd.c_encoding() == 4, "");
     }
 
     {
@@ -50,7 +50,7 @@
     constexpr weekday wd{sd};
 
     static_assert( wd.ok(), "");
-    static_assert(static_cast<unsigned>(wd) == 3, "");
+    static_assert( wd.c_encoding() == 3, "");
     }
 
 
@@ -59,7 +59,7 @@
     constexpr weekday wd{sd};
 
     static_assert( wd.ok(), "");
-    static_assert(static_cast<unsigned>(wd) == 2, "");
+    static_assert( wd.c_encoding() == 2, "");
     }
 
     {
@@ -67,7 +67,7 @@
     weekday wd{sd};
 
     assert( wd.ok());
-    assert(static_cast<unsigned>(wd) == 3);
+    assert( wd.c_encoding() == 3);
     }
 
     return 0;
diff --git a/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.pass.cpp b/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.pass.cpp
index 470b9d7..16b8873 100644
--- a/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.pass.cpp
+++ b/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.pass.cpp
@@ -15,10 +15,10 @@
 //  constexpr weekday(const sys_days& dp) noexcept;
 //  explicit constexpr weekday(const local_days& dp) noexcept;
 //
-//  explicit constexpr operator unsigned() const noexcept;
+//  unsigned c_encoding() const noexcept;
 
-//  Effects: Constructs an object of type weekday by initializing m_ with m.
-//    The value held is unspecified if d is not in the range [0, 255].
+//  Effects: Constructs an object of type weekday by initializing wd_ with wd == 7 ? 0 : wd
+//    The value held is unspecified if wd is not in the range [0, 255].
 
 #include <chrono>
 #include <type_traits>
@@ -32,18 +32,18 @@
 
     ASSERT_NOEXCEPT(weekday{});
     ASSERT_NOEXCEPT(weekday(1));
-    ASSERT_NOEXCEPT(static_cast<unsigned>(weekday(1)));
+    ASSERT_NOEXCEPT(weekday(1).c_encoding());
 
     constexpr weekday m0{};
-    static_assert(static_cast<unsigned>(m0) == 0, "");
+    static_assert(m0.c_encoding() == 0, "");
 
     constexpr weekday m1{1};
-    static_assert(static_cast<unsigned>(m1) == 1, "");
+    static_assert(m1.c_encoding() == 1, "");
 
     for (unsigned i = 0; i <= 255; ++i)
     {
         weekday m(i);
-        assert(static_cast<unsigned>(m) == i);
+        assert(m.c_encoding() == (i == 7 ? 0 : i));
     }
 
 // TODO - sys_days and local_days ctor tests
diff --git a/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.sys_days.pass.cpp b/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.sys_days.pass.cpp
index e00184a..18d48a3 100644
--- a/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.sys_days.pass.cpp
+++ b/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.sys_days.pass.cpp
@@ -42,7 +42,7 @@
     constexpr weekday wd{sd};
 
     static_assert( wd.ok(), "");
-    static_assert(static_cast<unsigned>(wd) == 4, "");
+    static_assert( wd.c_encoding() == 4, "");
     }
 
     {
@@ -50,7 +50,7 @@
     constexpr weekday wd{sd};
 
     static_assert( wd.ok(), "");
-    static_assert(static_cast<unsigned>(wd) == 3, "");
+    static_assert( wd.c_encoding() == 3, "");
     }
 
 
@@ -59,7 +59,7 @@
     constexpr weekday wd{sd};
 
     static_assert( wd.ok(), "");
-    static_assert(static_cast<unsigned>(wd) == 2, "");
+    static_assert( wd.c_encoding() == 2, "");
     }
 
     {
@@ -67,7 +67,7 @@
     weekday wd{sd};
 
     assert( wd.ok());
-    assert(static_cast<unsigned>(wd) == 3);
+    assert( wd.c_encoding() == 3);
     }
 
     return 0;
diff --git a/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/decrement.pass.cpp b/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/decrement.pass.cpp
index d574e1d..dcb301b 100644
--- a/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/decrement.pass.cpp
+++ b/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/decrement.pass.cpp
@@ -25,9 +25,9 @@
 constexpr bool testConstexpr()
 {
     WD wd{1};
-    if (static_cast<unsigned>(--wd) != 0) return false;
-    if (static_cast<unsigned>(wd--) != 0) return false;
-    if (static_cast<unsigned>(wd)   != 6) return false;
+    if ((--wd).c_encoding() != 0) return false;
+    if ((wd--).c_encoding() != 0) return false;
+    if ((wd).c_encoding()   != 6) return false;
     return true;
 }
 
@@ -45,9 +45,9 @@
     for (unsigned i = 0; i <= 6; ++i)
     {
         weekday wd(i);
-        assert((static_cast<unsigned>(--wd) == euclidian_subtraction<unsigned, 0, 6>(i, 1)));
-        assert((static_cast<unsigned>(wd--) == euclidian_subtraction<unsigned, 0, 6>(i, 1)));
-        assert((static_cast<unsigned>(wd)   == euclidian_subtraction<unsigned, 0, 6>(i, 2)));
+        assert(((--wd).c_encoding() == euclidian_subtraction<unsigned, 0, 6>(i, 1)));
+        assert(((wd--).c_encoding() == euclidian_subtraction<unsigned, 0, 6>(i, 1)));
+        assert(((wd)  .c_encoding() == euclidian_subtraction<unsigned, 0, 6>(i, 2)));
     }
 
   return 0;
diff --git a/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/increment.pass.cpp b/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/increment.pass.cpp
index bb62e01..a6dd954 100644
--- a/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/increment.pass.cpp
+++ b/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/increment.pass.cpp
@@ -25,9 +25,9 @@
 constexpr bool testConstexpr()
 {
     WD wd{5};
-    if (static_cast<unsigned>(++wd) != 6) return false;
-    if (static_cast<unsigned>(wd++) != 6) return false;
-    if (static_cast<unsigned>(wd)   != 0) return false;
+    if ((++wd).c_encoding() != 6) return false;
+    if ((wd++).c_encoding() != 6) return false;
+    if ((wd)  .c_encoding() != 0) return false;
     return true;
 }
 
@@ -45,9 +45,9 @@
     for (unsigned i = 0; i <= 6; ++i)
     {
         weekday wd(i);
-        assert((static_cast<unsigned>(++wd) == euclidian_addition<unsigned, 0, 6>(i, 1)));
-        assert((static_cast<unsigned>(wd++) == euclidian_addition<unsigned, 0, 6>(i, 1)));
-        assert((static_cast<unsigned>(wd)   == euclidian_addition<unsigned, 0, 6>(i, 2)));
+        assert(((++wd).c_encoding() == euclidian_addition<unsigned, 0, 6>(i, 1)));
+        assert(((wd++).c_encoding() == euclidian_addition<unsigned, 0, 6>(i, 1)));
+        assert(((wd)  .c_encoding() == euclidian_addition<unsigned, 0, 6>(i, 2)));
     }
 
   return 0;
diff --git a/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/iso_encoding.pass.cpp b/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/iso_encoding.pass.cpp
new file mode 100644
index 0000000..27d3f73
--- /dev/null
+++ b/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/iso_encoding.pass.cpp
@@ -0,0 +1,48 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+// UNSUPPORTED: c++98, c++03, c++11, c++14, c++17
+
+// <chrono>
+// class weekday;
+
+//  constexpr unsigned iso_encoding() const noexcept;
+//  Returns the underlying weekday, _except_ that returns '7' for Sunday (zero)
+//    See [time.cal.wd.members]
+
+#include <chrono>
+#include <type_traits>
+#include <cassert>
+
+#include "test_macros.h"
+
+template <typename WD>
+constexpr bool testConstexpr()
+{
+    WD wd{5};
+    return wd.c_encoding() == 5;
+}
+
+int main(int, char**)
+{
+    using weekday = std::chrono::weekday;
+
+    ASSERT_NOEXCEPT(                    std::declval<weekday&>().iso_encoding());
+    ASSERT_SAME_TYPE(unsigned, decltype(std::declval<weekday&>().iso_encoding()));
+
+    static_assert(testConstexpr<weekday>(), "");
+
+//  This is different than all the other tests, because the '7' gets converted to
+//  a zero in the constructor, but then back to '7' by iso_encoding().
+    for (unsigned i = 0; i <= 10; ++i)
+    {
+        weekday wd(i);
+        assert(wd.iso_encoding() == (i == 0 ? 7 : i));
+    }
+
+  return 0;
+}
diff --git a/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ok.pass.cpp b/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ok.pass.cpp
index f2f6e2e..86fa92e 100644
--- a/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ok.pass.cpp
+++ b/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ok.pass.cpp
@@ -28,11 +28,12 @@
 
     static_assert( weekday{0}.ok(), "");
     static_assert( weekday{1}.ok(), "");
-    static_assert(!weekday{7}.ok(), "");
+    static_assert( weekday{7}.ok(), "");  // 7 is transmorgified into 0 in the ctor
+    static_assert(!weekday{8}.ok(), "");
 
-    for (unsigned i = 0; i <= 6; ++i)
+    for (unsigned i = 0; i <= 7; ++i)
         assert(weekday{i}.ok());
-    for (unsigned i = 7; i <= 255; ++i)
+    for (unsigned i = 8; i <= 255; ++i)
         assert(!weekday{i}.ok());
 
   return 0;
diff --git a/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/plus_minus_equal.pass.cpp b/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/plus_minus_equal.pass.cpp
index d99b034..f79e7ff 100644
--- a/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/plus_minus_equal.pass.cpp
+++ b/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/plus_minus_equal.pass.cpp
@@ -24,12 +24,12 @@
 constexpr bool testConstexpr()
 {
     M m1{1};
-    if (static_cast<unsigned>(m1 += Ms{ 1}) !=  2) return false;
-    if (static_cast<unsigned>(m1 += Ms{ 2}) !=  4) return false;
-    if (static_cast<unsigned>(m1 += Ms{ 4}) !=  1) return false;
-    if (static_cast<unsigned>(m1 -= Ms{ 1}) !=  0) return false;
-    if (static_cast<unsigned>(m1 -= Ms{ 2}) !=  5) return false;
-    if (static_cast<unsigned>(m1 -= Ms{ 4}) !=  1) return false;
+    if ((m1 += Ms{ 1}).c_encoding() !=  2) return false;
+    if ((m1 += Ms{ 2}).c_encoding() !=  4) return false;
+    if ((m1 += Ms{ 4}).c_encoding() !=  1) return false;
+    if ((m1 -= Ms{ 1}).c_encoding() !=  0) return false;
+    if ((m1 -= Ms{ 2}).c_encoding() !=  5) return false;
+    if ((m1 -= Ms{ 4}).c_encoding() !=  1) return false;
     return true;
 }
 
@@ -49,15 +49,15 @@
     for (unsigned i = 0; i <= 6; ++i)
     {
         weekday wd(i);
-        assert((static_cast<unsigned>(wd += days{3}) == euclidian_addition<unsigned, 0, 6>(i, 3)));
-        assert((static_cast<unsigned>(wd)            == euclidian_addition<unsigned, 0, 6>(i, 3)));
+        assert(((wd += days{3}).c_encoding() == euclidian_addition<unsigned, 0, 6>(i, 3)));
+        assert(((wd)           .c_encoding() == euclidian_addition<unsigned, 0, 6>(i, 3)));
     }
 
     for (unsigned i = 0; i <= 6; ++i)
     {
         weekday wd(i);
-        assert((static_cast<unsigned>(wd -= days{4}) == euclidian_subtraction<unsigned, 0, 6>(i, 4)));
-        assert((static_cast<unsigned>(wd)            == euclidian_subtraction<unsigned, 0, 6>(i, 4)));
+        assert(((wd -= days{4}).c_encoding() == euclidian_subtraction<unsigned, 0, 6>(i, 4)));
+        assert(((wd)           .c_encoding() == euclidian_subtraction<unsigned, 0, 6>(i, 4)));
     }
 
   return 0;
diff --git a/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/literals.pass.cpp b/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/literals.pass.cpp
index 7529864..434ca11 100644
--- a/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/literals.pass.cpp
+++ b/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/literals.pass.cpp
@@ -51,13 +51,13 @@
     assert(std::chrono::Friday    == std::chrono::weekday(5));
     assert(std::chrono::Saturday  == std::chrono::weekday(6));
 
-    assert(static_cast<unsigned>(std::chrono::Sunday)    ==  0);
-    assert(static_cast<unsigned>(std::chrono::Monday)    ==  1);
-    assert(static_cast<unsigned>(std::chrono::Tuesday)   ==  2);
-    assert(static_cast<unsigned>(std::chrono::Wednesday) ==  3);
-    assert(static_cast<unsigned>(std::chrono::Thursday)  ==  4);
-    assert(static_cast<unsigned>(std::chrono::Friday)    ==  5);
-    assert(static_cast<unsigned>(std::chrono::Saturday)  ==  6);
+    assert(std::chrono::Sunday.c_encoding()    ==  0);
+    assert(std::chrono::Monday.c_encoding()    ==  1);
+    assert(std::chrono::Tuesday.c_encoding()   ==  2);
+    assert(std::chrono::Wednesday.c_encoding() ==  3);
+    assert(std::chrono::Thursday.c_encoding()  ==  4);
+    assert(std::chrono::Friday.c_encoding()    ==  5);
+    assert(std::chrono::Saturday.c_encoding()  ==  6);
 
   return 0;
 }
diff --git a/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/minus.pass.cpp b/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/minus.pass.cpp
index f296fc6..b35f427 100644
--- a/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/minus.pass.cpp
+++ b/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/minus.pass.cpp
@@ -62,7 +62,7 @@
         {
             weekday wd = weekday{i} - days{j};
             assert(wd + days{j} == weekday{i});
-            assert((static_cast<unsigned>(wd) == euclidian_subtraction<unsigned, 0, 6>(i, j)));
+            assert((wd.c_encoding() == euclidian_subtraction<unsigned, 0, 6>(i, j)));
         }
 
     for (unsigned i = 0; i <= 6; ++i)
diff --git a/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/plus.pass.cpp b/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/plus.pass.cpp
index 78d332b..5a5b32b 100644
--- a/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/plus.pass.cpp
+++ b/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/plus.pass.cpp
@@ -63,8 +63,8 @@
             weekday wd1 = weekday{i} + days{j};
             weekday wd2 = days{j} + weekday{i};
             assert(wd1 == wd2);
-            assert((static_cast<unsigned>(wd1) == euclidian_addition<unsigned, 0, 6>(i, j)));
-            assert((static_cast<unsigned>(wd2) == euclidian_addition<unsigned, 0, 6>(i, j)));
+            assert((wd1.c_encoding() == euclidian_addition<unsigned, 0, 6>(i, j)));
+            assert((wd2.c_encoding() == euclidian_addition<unsigned, 0, 6>(i, j)));
         }
 
   return 0;
diff --git a/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/weekday.pass.cpp b/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/weekday.pass.cpp
index dac1f7c..36182e1 100644
--- a/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/weekday.pass.cpp
+++ b/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/weekday.pass.cpp
@@ -35,7 +35,7 @@
     for (unsigned i = 1; i <= 50; ++i)
     {
         year_month_weekday ymwd0(year{1234}, month{2}, weekday_indexed{weekday{i}, 1});
-        assert(static_cast<unsigned>(ymwd0.weekday()) == i);
+        assert(ymwd0.weekday().c_encoding() == (i == 7 ? 0 : i));
     }
 
   return 0;
diff --git a/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/weekday_indexed.pass.cpp b/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/weekday_indexed.pass.cpp
index f089a8c..d551b7c 100644
--- a/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/weekday_indexed.pass.cpp
+++ b/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/weekday_indexed.pass.cpp
@@ -35,10 +35,11 @@
     for (unsigned i = 1; i <= 50; ++i)
     {
         year_month_weekday ymwd0(year{1234}, month{2}, weekday_indexed{weekday{i}, 1});
-        assert( static_cast<unsigned>(ymwd0.weekday_indexed().weekday()) == i);
+        assert( ymwd0.weekday_indexed().weekday().c_encoding() == (i == 7 ? 0 : i));
         assert( static_cast<unsigned>(ymwd0.weekday_indexed().index()) == 1);
+
         year_month_weekday ymwd1(year{1234}, month{2}, weekday_indexed{weekday{2}, i});
-        assert( static_cast<unsigned>(ymwd1.weekday_indexed().weekday()) == 2);
+        assert( ymwd1.weekday_indexed().weekday().c_encoding() == 2);
         assert( static_cast<unsigned>(ymwd1.weekday_indexed().index()) == i);
     }
 
diff --git a/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/ok.pass.cpp b/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/ok.pass.cpp
index c18b926..2730ad6 100644
--- a/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/ok.pass.cpp
+++ b/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/ok.pass.cpp
@@ -37,11 +37,11 @@
 
     static_assert(!year_month_weekday_last{year{-32768}, January, weekday_last{Tuesday}}.ok(),    ""); // Bad year
     static_assert(!year_month_weekday_last{year{2019},   month{}, weekday_last{Tuesday}}.ok(),    ""); // Bad month
-    static_assert(!year_month_weekday_last{year{2019},   January, weekday_last{weekday{7}}}.ok(), ""); // Bad day
+    static_assert(!year_month_weekday_last{year{2019},   January, weekday_last{weekday{8}}}.ok(), ""); // Bad day
 
     static_assert(!year_month_weekday_last{year{-32768}, month{}, weekday_last{Tuesday}}.ok(),    ""); // Bad year & month
-    static_assert(!year_month_weekday_last{year{2019},   month{}, weekday_last{weekday{7}}}.ok(), ""); // Bad month & day
-    static_assert(!year_month_weekday_last{year{-32768}, January, weekday_last{weekday{7}}}.ok(), ""); // Bad year & day
+    static_assert(!year_month_weekday_last{year{2019},   month{}, weekday_last{weekday{8}}}.ok(), ""); // Bad month & day
+    static_assert(!year_month_weekday_last{year{-32768}, January, weekday_last{weekday{8}}}.ok(), ""); // Bad year & day
 
     static_assert( year_month_weekday_last{year{2019},   January, weekday_last{Tuesday}}.ok(),    ""); // All OK
 
diff --git a/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/weekday.pass.cpp b/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/weekday.pass.cpp
index 1de0b83..e62dc7f 100644
--- a/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/weekday.pass.cpp
+++ b/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/weekday.pass.cpp
@@ -35,7 +35,7 @@
     for (unsigned i = 1; i <= 50; ++i)
     {
         year_month_weekday_last ymwdl(year{1}, month{1}, weekday_last{weekday{i}});
-        assert(static_cast<unsigned>(ymwdl.weekday()) == i);
+        assert(ymwdl.weekday().c_encoding() == (i == 7 ? 0 : i));
     }
 
   return 0;