WeekCal supports iOS Full-screen mode, however, this mode can obscure the first week of the month view.
When full-screen mode is enabled, the top and bottom bar (configurable) will show on top of the contents of the calendar, until they are dismissed by either a single finger tap or a double finger tap, depending on your settings.
The first week of Month view is hidden
This happens when you have full-screen mode enabled: the top bar will fall over the contents until it is dismissed.
If you do not want this behavior, please set Settings > General > Full screen to OFF.