Each morning, Migraine Sentry reads your overnight data and gives you a single, plain read on the day ahead: your vulnerability level. It's designed to be a quiet heads-up you can glance at over coffee, not a number to obsess over.
What the levels mean
Your forecast is shown as one of three levels. Under the hood it's a 0–100 score that weighs last night's signals (sleep, HRV, resting heart rate, barometric pressure, the day's weather) plus yesterday's check-in answers (stress, alcohol, water, skipped meals) against your personal baseline and the patterns that preceded your own past migraines. The levels describe how far today's signals sit from your normal, not a percentage chance that a migraine will happen.
| Level | What it's saying | A good response |
|---|---|---|
| Low | Your signals look close to your baseline. | Carry on as normal. |
| Moderate | One or two signals have drifted from your usual pattern. | Take the suggested action; keep an easy pace. |
| Elevated | Several signals linked to your attacks are lining up. | Act early: hydrate, protect your routine, keep medication handy. |
Why today's level changed
Tap the forecast card to see the signals behind it. Migraine Sentry shows the handful that moved most (for example a short night, a falling barometer, or an overnight HRV dip), each with a short, concrete action.
- Sleep: total time, schedule shifts, and how fragmented the night was
- HRV & resting heart rate: overnight autonomic shifts
- Barometric pressure & weather: overnight drops and the pressure forecast for the hours ahead
- Cycle phase: if you track your menstrual cycle
- Yesterday's check-in: several drinks, high stress, low water or skipped meals the day before
When forecasts begin
Your first forecast appears once Migraine Sentry has both 7 days of health data and 3 logged migraines: before that, it would be guessing. Because the app imports up to 90 days of your existing Apple Health history during setup, the data half is often ready within minutes. The picture sharpens by your fifth migraine and keeps improving as you log.
The forecast arrives each morning and holds for the day; the live signals below it track anything that shifts after. On the day an attack ends, the forecast steps aside for a recovery view and returns the next morning.
If there's no forecast today
Occasionally a morning has too little to read: for example, no sleep or overnight data synced and no measurable weather signal. Migraine Sentry says so rather than inventing a number. Opening the app after your Apple Watch syncs usually resolves it.
Why a morning forecast didn't notify you
If you swipe Migraine Sentry away in the App Switcher, iOS pauses its background activity, including the early-morning forecast run, until you next open it. Leave it in the background; iOS manages its energy automatically. Already-scheduled reminders still arrive, but a fresh morning forecast won't run while the app is force-quit.
Acting on your forecast
The most useful thing you can do with a Moderate or Elevated morning is small and early: protect your sleep tonight, keep water within reach, and take the one action the card suggests. Over time, logging how the day actually went is what makes the next forecast sharper.