Online alarm clock for 11:15 am
While you watch the clock for the school assembly, set the alarm for 11:15 am so the flag is ready to be raised at the appointed moment. That leaves the rest of the morning easy to track, with 12:00 pm providing a natural marker for whatever follows the ceremony. Keep the flag, clips and rope together while you wait, rather than leaving the final check until the signal sounds.
The assembly setting should guide the alarm tone. A softer sound suits a quiet hall where pupils or speakers may already be gathered, while a more persistent tone can help outdoors among conversation and playground noise. Test the chosen volume briefly from where you will stand. The flag could be raised late if you close the alarm page or allow the phone to sleep, because a browser alarm cannot sound in either situation; keep it active until 11:15 am, with a separate school clock as a fallback.
Before heading out for the late-morning assembly, check whether the flag feels damp and whether the air is still or breezy. New Zealand humidity can leave folded fabric clinging to itself, so loosen it gently and make sure the halyard moves freely. At 11:15 am, standing on the windward side can also stop the cloth wrapping around the pole as it rises.