diff --git a/src/pretix/base/reldate.py b/src/pretix/base/reldate.py
index e82950cbe..8ee176c35 100644
--- a/src/pretix/base/reldate.py
+++ b/src/pretix/base/reldate.py
@@ -71,7 +71,7 @@ class RelativeDateWrapper:
             else:
                 base_date = getattr(event, self.data.base_date_name) or event.date_from
 
-            oldoffset = base_date.utcoffset()
+            oldoffset = base_date.astimezone(tz).utcoffset()
             new_date = base_date.astimezone(tz) - datetime.timedelta(days=self.data.days_before)
             if self.data.time:
                 new_date = new_date.replace(