diff --git a/app/views/calendars/show.ics.erb b/app/views/calendars/show.ics.erb
index 30654a4..564f4e9 100644
--- a/app/views/calendars/show.ics.erb
+++ b/app/views/calendars/show.ics.erb
@@ -2,7 +2,22 @@ BEGIN:VCALENDAR
 VERSION:2.0
 PRODID:http://www.example.com/calendarapplication/
 METHOD:PUBLISH
-X-WR-TIMEZONE:Vienna
+X-WR-TIMEZONE:Europe/Vienna
+BEGIN:VTIMEZONE
+TZID:Europe/Vienna
+BEGIN:DAYLIGHT
+TZOFFSETFROM:+0100
+DTSTART:19810329T020000
+RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=-1SU
+TZNAME:MESZ
+END:DAYLIGHT
+BEGIN:STANDARD
+TZOFFSETFROM:+0200
+DTSTART:19961027T030000
+RRULE:FREQ=YEARLY;BYMONTH=10;BYDAY=-1SU
+TZNAME:MEZ
+END:STANDARD
+END:VTIMEZONE
 <% @calendar.calentries.each do |entry| %>
 <%= render entry %>
 <% end %>
diff --git a/app/views/calentries/_calentry.ics.erb b/app/views/calentries/_calentry.ics.erb
index d3f61d7..f73a16f 100644
--- a/app/views/calentries/_calentry.ics.erb
+++ b/app/views/calentries/_calentry.ics.erb
@@ -5,7 +5,7 @@ LOCATION:Vienna
 SUMMARY:<%= calentry.name %>
 DESCRIPTION: <%= link_to calentry.name.to_s, polymorphic_path(calentry.object) %><%= calentry.summary %>
 CLASS:PUBLIC
-DTSTART:<%= calentry.start.strftime "%Y%m%dT%H%M%S" %>
-DTEND:<%= calentry.ende.strftime "%Y%m%dT%H%M%S" %>
-DTSTAMP:<%= calentry.start.strftime "%Y%m%dT%H%M%S" %>
+DTSTART;TZID=Europe/Vienna:<%= calentry.start.strftime "%Y%m%dT%H%M%S" %>
+DTEND;TZID=Europe/Vienna:<%= calentry.ende.strftime "%Y%m%dT%H%M%S" %>
+DTSTAMP;TZID=Europe/Vienna:<%= calentry.start.strftime "%Y%m%dT%H%M%S" %>
 END:VEVENT
\ No newline at end of file