1 files changed, 5 insertions, 1 deletions
diff --git a/src/corelib/global/qtenvironmentvariables.cpp b/src/corelib/global/qtenvironmentvariables.cpp
index 47fc8f7eec..cf5955902a 100644
--- a/src/corelib/global/qtenvironmentvariables.cpp
+++ b/src/corelib/global/qtenvironmentvariables.cpp
@@ -353,6 +353,10 @@ void qTzSet()
 time_t qMkTime(struct tm *when)
 {
     const auto locker = qt_scoped_lock(environmentMutex);
+#if defined(Q_OS_WIN)
+    // QTBUG-83881 MS's mktime() seems to need _tzset() called first.
+    _tzset();
+#endif
     return mktime(when);
 }
 
@@ -404,7 +408,7 @@ QString qTzName(int dstIndex)
 {
     char name[512];
     bool ok;
-#if defined(Q_CC_MSVC)
+#if defined(_UCRT)  // i.e., MSVC and MinGW-UCRT
     size_t s = 0;
     {
         const auto locker = qt_scoped_lock(environmentMutex);