Calendar icon shows correct date but wrong day is highlighted when Calendar is opened

As I write, it is Wednesday, July 29th. In my Dock, the Calendar icon displays "29" correctly. However, when I open Calendar, the highlighted day is Thursday, July 30th. This is the case in Week, Month, and Year views. In Day view, Thursday the 30th displays.

In System Preferences the date and time are set automatically, and the mini calendar correctly shows the date as Wednesday the 29th, as does the menu bar.

My iPhone Calendar does not have this problem—only my Mac.

When I access iCloud on the web, the time zone is correct in the Settings. The iCloud Calendar preferences are set to enable time zone support. The iCloud Calendar on the web correctly highlights July 29th as the current day.

Using a Macbook Pro Retina running OS X Mavericks 10.9.5.

Any help much appreciated!

Eric