diff --git a/src/calibre/utils/date.py b/src/calibre/utils/date.py
index 7576c850c1..f19631be23 100644
--- a/src/calibre/utils/date.py
+++ b/src/calibre/utils/date.py
@@ -6,12 +6,12 @@ __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 import re
-from datetime import datetime, time as dtime, timedelta, MINYEAR, MAXYEAR
+from datetime import MAXYEAR, MINYEAR, datetime, time as dtime, timedelta
 from functools import partial
 
 from calibre import strftime
-from calibre.constants import iswindows, ismacos, preferred_encoding
-from calibre.utils.iso8601 import utc_tz, local_tz, UNDEFINED_DATE
+from calibre.constants import ismacos, iswindows, preferred_encoding
+from calibre.utils.iso8601 import UNDEFINED_DATE, local_tz, utc_tz
 from calibre.utils.localization import lcdata
 from polyglot.builtins import native_string_type
 
@@ -152,24 +152,33 @@ def dt_factory(time_t, assume_utc=False, as_utc=True):
 
 
 def safeyear(x):
-    return min(max(x, MINYEAR), MAXYEAR)
+    return min(max(MINYEAR, x), MAXYEAR)
 
 
 def qt_to_dt(qdate_or_qdatetime, as_utc=True):
+    from qt.core import Qt, QDateTime
     o = qdate_or_qdatetime
     if o is None:
         return UNDEFINED_DATE
-    if hasattr(o, 'toUTC'):
-        # QDateTime
-        o = o.toUTC()
-        d, t = o.date(), o.time()
-        try:
-            ans = datetime(safeyear(d.year()), d.month(), d.day(), t.hour(), t.minute(), t.second(), t.msec()*1000, utc_tz)
-        except ValueError:
-            ans = datetime(safeyear(d.year()), d.month(), 1, t.hour(), t.minute(), t.second(), t.msec()*1000, utc_tz)
-        if not as_utc:
-            ans = ans.astimezone(local_tz)
-        return ans
+    if hasattr(o, 'toUTC'): # QDateTime
+        def c(o: QDateTime, tz=utc_tz):
+            d, t = o.date(), o.time()
+            try:
+                return datetime(safeyear(d.year()), d.month(), d.day(), t.hour(), t.minute(), t.second(), t.msec()*1000, tz)
+            except ValueError:
+                return datetime(safeyear(d.year()), d.month(), 1, t.hour(), t.minute(), t.second(), t.msec()*1000, tz)
+
+        # DST causes differences in how python and Qt convert automatically from local to UTC, so convert explicitly ourselves
+        # QDateTime::toUTC() and datetime.astimezone(utc_tz) give
+        # different results for datetimes in the local_tz when DST is involved. Sigh.
+        spec = o.timeSpec()
+        if spec == Qt.TimeSpec.LocalTime:
+            ans = c(o, local_tz)
+        elif spec == Qt.TimeSpec.UTC:
+            ans = c(o, utc_tz)
+        else:
+            ans = c(o.toUTC(), utc_tz)
+        return ans.astimezone(utc_tz if as_utc else local_tz)
 
     try:
         dt = datetime(safeyear(o.year()), o.month(), o.day()).replace(tzinfo=_local_tz)
@@ -178,14 +187,16 @@ def qt_to_dt(qdate_or_qdatetime, as_utc=True):
     return dt.astimezone(_utc_tz if as_utc else _local_tz)
 
 
-def qt_from_dt(d, as_utc=False, assume_utc=False):
-    from qt.core import QDateTime, QTimeZone
+def qt_from_dt(d: datetime, as_utc=False, assume_utc=False):
+    from qt.core import QDate, QDateTime, QTime, QTimeZone
     if d.tzinfo is None:
         d = d.replace(tzinfo=utc_tz if assume_utc else local_tz)
-    d = d.astimezone(utc_tz)
-    ans = QDateTime.fromMSecsSinceEpoch(int(d.timestamp() * 1000), QTimeZone.utc())
-    if not as_utc:
-        ans = ans.toLocalTime()
+    if as_utc:
+        d = d.astimezone(utc_tz)
+        ans = QDateTime.fromMSecsSinceEpoch(int(d.timestamp() * 1000), QTimeZone.utc())
+    else:
+        d = d.astimezone(local_tz)
+        ans = QDateTime(QDate(d.year, d.month, d.day), QTime(d.hour, d.minute, d.second, int(d.microsecond / 1000)))
     return ans