Hah, nice. I like the fuzzy time thing.
You could even tie the fuzziness to your survival skill somehow. With 0 survival you only know Night, dawn, day, and dusk. With a little survival you could get more specific (Midnight, After Midnight, Dawn, Morning, Afternoon, Evening, Dusk, Before Midnight), and eventually giving you an hourly estimate based on the position of the sun/moon/stars etc.
When it’s cloudy/rainy, you could force it back to Night/Dawn/Day/Dusk regardless of your survival skill.
Anyway, good on the watch thing. Make sure that the alarm has a chance of alerting nearby enemies. 