You can set date properties for a data source. To do so, right-click (control-click on Mac) a data source in the Data pane and choose Date Properties:
The options in the Date Properties dialog box are:
Default calendar - Specifies which calendar system to use: Standard Gregorian or ISO-8601 Week-Based. You can freely switch between the calendar types with the dates in your view, but setting the default calendar will determine how dates are used upon initially dragging them into your view. See Date Functions(Link opens in a new window)
Week start - Specifies which day is considered the first day of the week. You can override the Week start value you set at the data source level by including a
start_of_weekvalue with certain date functions (
DATETRUNC). See Date Functions(Link opens in a new window).
The initial value for this setting is in some cases determined by your data source. If the data source does not initialize the start-of-week day, then Tableau consults the system's locale settings.The day which is considered the first day of the week varies from region to region. For example, Sunday is the first day of the week in the US, while Monday is the first day in the EU.
This setting is disabled for multidimensional data sources because this information is defined when cube designer creates the date/time dimension.
After a data source is created, the Week start value does not automatically change if for any reason the default start-of-week setting changes in the host operating system (for example, if the data source is uploaded to Tableau Server in a different country). Calendar controls reflect the workbook locale rather than the data source's Week start setting. The exception is that a week trunc start of week that shows the week number in it will use the data source's Week start setting in order to provide a consistent week number value in the calendar.
Fiscal year start - Specifies which month is considered the first month of the fiscal year. To specify whether a date dimension uses the standard calendar (Jan. 1 - Dec. 31) or the fiscal calendar, right-click (control-click on Mac) the field in the Data pane and select Default Properties > Calendar Type and then select Standard Calendar or Fiscal Calendar. For any date field in the view, you can then specify whether to use the standard calendar or the fiscal calendar. For details, see Fiscal Dates(Link opens in a new window).
Date format - Specifies the default format for data dimensions, as displayed, for example, in tooltips.To override the default date format for a date dimension, right-click (control-click on Mac) the field in the Data pane and select Default Properties > Date Format and then select one of the available formats.
Day of the week sorting
If you are working in a language for which Tableau does not provide a local version, set your workbook locale to assure that Tableau can sort the days of the week in the correct chronological order. Otherwise, Tableau will sort the names of the days alphabetically. For information on setting the locale, see Language and Locale.
If none of the supported locales is appropriate, you can sort the days of the week manually. See Sort Data in a Visualization(Link opens in a new window).
Supported date formats
When working with dates, Tableau retrieves date formats automatically from the data source.
For a list of supported date formats, see the table of supported date format symbols in Custom Date Formats.