The "Date/Time" tab only allows checking against an absolute date/time value.
If you want to check a specific part of a date/time value, you'll want to use the "Text" tab combined with the appropriate token for the part you want to check.
E.G. to check whether it's currently Tuesday, you could do
Begin Text Compare : [{DATEDAYOFWEEK}] Equals 'Tuesday'
Write [Blue] 'Yes, it is Tuesday' to log
End Condition
Press F1 while VoiceAttack has focus to open VoiceAttackHelp.pdf in your default PDF viewer; The "Text (and Text-To-Speech) Tokens" section lists the available date/time-related tokens.