diff --git a/date.h b/date.h
index d793a8d..4d55914 100644
--- a/date.h
+++ b/date.h
@@ -2769,7 +2769,7 @@ year_month_weekday::ok() const NOEXCEPT
         return false;
     if (wdi_.index() <= 4)
         return true;
-    auto d2 = wdi_.weekday() - date::weekday(y_/m_/1) + days((wdi_.index()-1)*7 + 1);
+    auto d2 = wdi_.weekday() - date::weekday(static_cast<sys_days>(y_/m_/1)) + days((wdi_.index()-1)*7 + 1);
     return static_cast<unsigned>(d2.count()) <= static_cast<unsigned>((y_/m_/last).day());
 }
 
diff --git a/tz.cpp b/tz.cpp
index de2090f..ed7acd4 100644
--- a/tz.cpp
+++ b/tz.cpp
@@ -926,7 +926,7 @@ MonthDayTime::to_sys_days(date::year y) const
     case lteq:
         {
             auto const x = y/u.month_day_weekday_.month_day_;
-            auto const wd1 = weekday(x);
+            auto const wd1 = weekday(static_cast<sys_days>(x));
             auto const wd0 = u.month_day_weekday_.weekday_;
             return sys_days(x) - (wd1-wd0);
         }
@@ -935,7 +935,7 @@ MonthDayTime::to_sys_days(date::year y) const
     }
     auto const x = y/u.month_day_weekday_.month_day_;
     auto const wd1 = u.month_day_weekday_.weekday_;
-    auto const wd0 = weekday(x);
+    auto const wd0 = weekday(static_cast<sys_days>(x));
     return sys_days(x) + (wd1-wd0);
 }
 
@@ -965,7 +965,7 @@ MonthDayTime::canonicalize(date::year y)
     case lteq:
         {
             auto const x = y/u.month_day_weekday_.month_day_;
-            auto const wd1 = weekday(x);
+            auto const wd1 = weekday(static_cast<sys_days>(x));
             auto const wd0 = u.month_day_weekday_.weekday_;
             auto const ymd = year_month_day(sys_days(x) - (wd1-wd0));
             u.month_day_ = ymd.month()/ymd.day();
@@ -976,7 +976,7 @@ MonthDayTime::canonicalize(date::year y)
         {
             auto const x = y/u.month_day_weekday_.month_day_;
             auto const wd1 = u.month_day_weekday_.weekday_;
-            auto const wd0 = weekday(x);
+            auto const wd0 = weekday(static_cast<sys_days>(x));
             auto const ymd = year_month_day(sys_days(x) + (wd1-wd0));
             u.month_day_ = ymd.month()/ymd.day();
             type_ = month_day;