Smart migraine tracking that stays on your device. Megrim is an open-source, offline-first migraine diary that helps you find your personal triggers. The app automatically adds time-of-day, season, daylight, and moon context to your entries — and, if you opt in, local weather and barometric pressure — calculating correlations entirely on your phone. With no accounts, no cloud servers, and zero tracking, your health data stays completely private and under your control. What's inside: * Automatic on-device enrichment — daylight hours, time of day, season, and moon phase computed locally; opt in to add local weather and barometric-pressure change (24h/48h). No manual entry. * Real personal analytics — trends by day-of-week, time-of-day, season, daylight, pressure change, and moon phase, plus a "suspected factors" card that uses odds ratios over your own log. * Your data stays yours — on-device storage only, with full export and import (JSON and CSV). * No accounts, no servers, no telemetry — by default the app makes no automatic network requests (the only exception is the place-name search you type when setting your home location). Weather enrichment is opt-in; when enabled, the only network request is to Open-Meteo.com, to fetch weather for the approximate (~1 km rounded) location and date of the entries you create. * Free and open source (GPL-3.0-or-later). Megrim is a personal diary and is NOT a medical device. It does not diagnose, treat, cure, or prevent any condition. "Suspected factors" are statistical associations in your own log — association is not causation. Always consult a qualified healthcare professional. Weather data by Open-Meteo.com.