Online alarm clock for 3:43 am
Handing the Marlborough vineyard frost check to the next person at 3:43 am means making the changeover unmistakable. Set the alarm for the agreed handover time and leave a brief note naming the blocks or rows still to inspect. With 4:00 am approaching, there is enough time to pass on observations, keys and any gear without turning the shift change into a rushed conversation.
During the vineyard handover, keep this alarm page in the foreground if you can. A browser may reduce activity on a page sent into the background, particularly when another app occupies the screen, so check that the countdown is still moving after switching back. The vineyard alert also depends on the browser remaining active and the computer or phone staying awake; if either closes or sleeps, the sound may not happen. For a frost inspection that cannot wait, use a separate alarm as backup.
Before the next person heads between the vines in the dark, lower the screen brightness enough to avoid a glaring rectangle inside the vehicle or shed. Use a warm display setting if one is available, then put the phone down once 3:43 am is set. Keeping the screen off until the alarm is due helps preserve night vision for checking the rows, gates and track ahead.