All of the above plus some . . .
In the U.S. the standard NOAA report is for a calendar day (0000 to 2359) but NWS Cooperative Observers and CoCoRaHS stations are requested to report for the 24 hours ending at 0700 (local time) each day. Some observers who report their observations to local TV stations are reporting precip for the 24 hours since the previous evening’s main newscast and temperature extremes for the calendar day. And, for additional fun, in New York state, the NYS Mesonet stations (on their Web sites) report precip for the past 24, 72 & 168 hours rolling totals (ie: 1,3 & 7 days) and don’t report temperature extremes numerically at all but let the user try to pick them off of their meteogram graphs.
So . . . I would say that my opinion is that there should be two options. 1. the NOAA standard calendar day (like shown graphically in the fully zoomed-out WF app graphs). And 2. a screen that allows the user to enter a date and time and returns the extremes for the preceeding 24 hours.
For me . . . I solve the problem by using @GaryFunk’s WFArchiver to capture all UDP weather data into an SQL database on a Raspberry Pi and then query the database for the extremes or sums for whatever date/time range I need at that moment.
A very long answer to the poll choice of “other”.