diff --git a/mozilla/calendar/locales/en-US/chrome/calendar/dateFormat.properties b/mozilla/calendar/locales/en-US/chrome/calendar/dateFormat.properties
index aad685742c0..9f5752a78d5 100644
--- a/mozilla/calendar/locales/en-US/chrome/calendar/dateFormat.properties
+++ b/mozilla/calendar/locales/en-US/chrome/calendar/dateFormat.properties
@@ -80,13 +80,13 @@ day.6.Mmm=Fri
 day.7.Mmm=Sat
 
 # Can someone tell me why were not counting from zero?
-day.1.short=S
+day.1.short=Su
 day.2.short=M
-day.3.short=T
+day.3.short=Tu
 day.4.short=W
-day.5.short=T
+day.5.short=Th
 day.6.short=F
-day.7.short=S
+day.7.short=Sa
 
 am-string=AM
 pm-string=PM