diff --git a/src/applications/calendar/storage/PhabricatorCalendarEvent.php b/src/applications/calendar/storage/PhabricatorCalendarEvent.php
--- a/src/applications/calendar/storage/PhabricatorCalendarEvent.php
+++ b/src/applications/calendar/storage/PhabricatorCalendarEvent.php
@@ -1024,6 +1024,10 @@
 
     $set = new PhutilCalendarRecurrenceSet();
 
+    if ($this->viewerTimezone) {
+      $set->setViewerTimezone($this->viewerTimezone);
+    }
+
     $rrule = $this->newRecurrenceRule();
     if (!$rrule) {
       return null;