I’m aware that there is an international standard on how to display date-time, ISO 8601 (http://en.wikipedia.org/wiki/ISO_8601). But we all know that it’s not that common. Maybe it is in engineering, but certainly not in design or everyday life.
I’ve seen quite a few ways to display time and one of those uses ‘ to denote minutes and ” to denote seconds. (Like in John Cage’s 4′33″) I may be wrong but it seems obvious that this is “inspired” by notation for angles. Therefor I’m wondering wether it’s ok to use ° (degree) symbol to denote hours. What do you think?
e.g. 1°35′ (for one hour and thirty five minutes)
I plan to use it to denote short time spans, durations. e.g. “It will take about 2°15′ to finish X.”
The question asks about prime and double-prime symbols for minutes and seconds, which have been used for ages, and even feature in a piece of piano music (or what would be piano music, if there were a note played).
However it then veers off from the question title to ask about extending this to using degree ° for hours.
Prime/Double prime ′ and ″ can mean angular minutes and seconds or time minutes and seconds, or even feet and inches, but their variable meaning is context-dependent and easily grasped. The degree symbol universally means degrees: to force into a square-shaped hole for hours would be to make it unexpected and difficult to understand.
If you want a single-character for hours to complement ′ and ″, use h.
It will take about 2h15′ to finish X.