Migraine Weather Data & Methodology
How we source real-time barometric pressure, calculate migraine risk, and what the research says about weather as a trigger.
Data Source
All pressure readings in the calculator and city forecast pages are fetched directly from Open-Meteo, an open-source meteorological API. Open-Meteo aggregates output from multiple national weather services:
- NOAA GFS / NAM — primary US coverage
- ECMWF — European Centre for Medium-Range Weather Forecasts, global coverage
- Meteo-France ARPEGE — Europe and North Atlantic
- DWD ICON — German Weather Service, high resolution over Europe
- Bureau of Meteorology — Australia/NZ coverage
All pressure values are sea-level corrected (mean sea level pressure, MSLP), consistent with the values reported in published migraine research. For high-altitude cities like Denver, this means the displayed pressure represents what an equivalent sea-level station would read — the relative changes (drops, rises) remain directly comparable to the research thresholds.
Risk Calculation Methodology
Our risk scores combine two independent risk factors derived from the published literature:
Factor 1: 24-Hour Pressure Drop
Low risk: Drop ≤ 3 hPa in 24h
Moderate risk: Drop 3–8 hPa in 24h
High risk: Drop > 8 hPa in 24h
Factor 2: Absolute Pressure Level
Low risk: ≥ 1005 hPa
Additional risk: 1000–1005 hPa
Additional risk: < 1000 hPa
The final risk level is the higher of the two factors, with interactions (e.g., below-1000 hPa combined with any meaningful drop) escalating to the next level. Rising pressure is not currently scored as a risk factor — while some individuals report sensitivity to pressure increases, the research evidence is less consistent than for drops.
Research Basis
The link between barometric pressure and migraines is one of the more robustly studied environmental trigger relationships:
Fukui et al. (2008) — Cephalalgia
Prospective study of 28 migraine patients over 2 years. Found significantly higher migraine incidence on days with 5+ hPa pressure drops versus stable days. This study established the 5 hPa threshold widely cited in clinical practice.
Prince et al. (2004) — Neurology
Survey of 1,207 migraineurs found 62% identified weather as a trigger. Among these, barometric pressure change was the most frequently cited specific meteorological factor.
Mukamal et al. (2009) — Neurology
Population study linking low ambient pressure with increased emergency department visits for headache, supporting the absolute pressure threshold component of our risk model.
These risk scores represent population-level associations. They are not a substitute for personal tracking. Your individual pressure sensitivity — the specific drop magnitude that reliably precedes your attacks — can only be determined from your own longitudinal data.
Limitations
- •Population averages only. These thresholds are derived from group-level studies. Your personal trigger threshold may be different — higher, lower, or absent entirely.
- •Pressure is one variable. Weather includes temperature, humidity, light intensity, and thunderstorm electrical fields — all of which have been studied as potential migraine triggers but are not included in the current risk score.
- •Not medical advice. These tools are informational. Decisions about preventive medication, trigger avoidance, and treatment should be made with your healthcare provider.
- •Altitude correction. For cities at high altitude (Denver, Mexico City, etc.), the displayed MSLP is corrected to sea level. This correction is standard but introduces minor inaccuracy for inland high-altitude stations.