Current Alert Manager has limited abilities for alert actions time management.
You can only choose the days of the week and one time interval for all selected days.
Unfortunately you can't choose individual time interval for each day or multiple time intervals for the day.
I.e: I'm ok to have email alerts 24x7, but I need SMS alerts only outside business hours and whole day during weekends/public holidays.
I found workaround for weekends:
I have to create the same trigger/reset actions for different timeframes, i.e.: one for Sat/Sun and second for Mon-Fri.
But I’m not sure if Mon-Fri action will works well as I need timeframes 0:00-8:30 and 17:00-24:00 so I type “From 5:00PM To 8:30AM” in the Time of the Day tab.
I think it could be good idea to have individual timeframes for each day instead of one timeframe for all days.
I saw something similar in the Parental Control 'Time Limits' for Windows7 (see attached file).
It's not the best option to copy, but something to start :-)
Another option – ability to create different custom timeframe template which could be applied to any day of the week.
Anyway there is no workaround for public holiday exceptions. Some of them has fixed days, like Christmas/New Year days, some flexible like Good Friday/Easter Monday.
I’d like to have an option to choose days from calendar and mark them to use one of pre-defined timeframe templates.
Not sure why I never thought to put a feature request in considering the number of times I've had to write multiple alert rules to do exactly what you are referring to. Great idea!