iPhone/iPad calendars not synching properly with Microsoft Outlook calendar

Question

I keep experiencing the same problem with my iPhone calendar when I enter a multi-day calendar event into Microsoft Outlook. For example, when I enter an event into the Outlook calendar starting 9am on 10/26 and ending 9am 10/27, it will later appear in my iPhone calendar as an "All-day" event on 10/27 and/or 10/28. Can somebody explain how to fix this problem? Thank you