Clock Format: Ubuntu | change-edit-panel-digital-clock-format

gistfile1.txt

What works for me:

    %x, %r


Change the 'Clock Format' codes as supplied below:

    %a, %B, %x, %r


You can change the style of tooltip. To edit tool tip format simply paste the time codes written below in the 'Tooltip Format' field.

    %B, %y %A, %x


Press 'Close' button to active the action. You can select the way you want to show the text. Bold it or not. To show 'Tooltip' only or centralize the text by clicking on radio button.  You can change the codes from the list below if you like to display more information in 'Digital Clock' are in LXPanel.

    %a - The abbreviated weekday name (Sun)
    %A - The full weekday name (Sunday)
    %b - The abbreviated month name (Jan)
    %B - The full month name (January)
    %d - Day of the month (01..31)
    %e - Day of the month (1..31)
    %H - Hour of the day, 24-hour clock (00..23)
    %I - Hour of the day, 12-hour clock (01..12)
    %l - Hour of the day ()
    %j - Day of the year (001..366)
    %m - Month of the year (01..12)
    %M - Minute of the hour (00..59)
    %p - Meridian indicator (AM or PM)
    %S - Second of the minute (00..60)
    %w - Day of the week (Sunday is 0, 0..6)
    %y - Year without a century (00..99)
    %Y - Year with century
    %Z - Time zone name
    %% - Literal % character


Source: https://netgator.blogspot.com/2012/09/change-edit-panel-digital-clock-format.html