What Barometric Pressure Triggers Migraines?
The specific pressure numbers linked to migraine, in hPa and inHg, what counts as a meaningful drop, and why rate of change matters more than the absolute reading.
Research most often links migraines to a drop of about 6–10 hPa (roughly 0.18–0.30 inHg) from normal pressure of about 1013 hPa (29.92 inHg), usually over a few hours as a storm approaches. There's no single magic number. What matters most is a rapid fall rather than the absolute reading, and individual sensitivity varies.
Educational use only. This article summarizes published research and reputable sources for general information. It is not medical advice and is not a substitute for diagnosis or treatment by a qualified healthcare professional. Always consult your doctor about your migraines and before changing anything about your care.
“What pressure gives me a migraine?” is one of the most common questions weather-sensitive people ask, and most articles dodge it. Here are the actual numbers, with one important caveat: the change matters more than the reading.
The reference points
- Normal (standard) sea-level pressure: about 1013 hPa, or 29.92 inHg.
- High pressure: above about 1013 hPa, typically clear, settled weather.
- Low pressure: below about 1005 hPa, meaning clouds, rain, and storms.
- Storm range where attacks cluster: roughly 1000–1007 hPa.
The number that matters most is the drop
The single most useful figure from the research is the size of the pressure drop, not the absolute value. In Okuma and colleagues’ study, migraines were most frequent when pressure had fallen by about 6–10 hPa from the 1013 hPa baseline. Converted to the units a US weather app shows, that’s roughly a 0.18–0.30 inHg drop.
Here’s a practical way to think about thresholds over a 6-hour window:
| Pressure drop (over about 6 hours) | What it usually means | Migraine relevance |
|---|---|---|
| Under about 4 hPa (≈0.12 inHg) | Normal daily variation | Low |
| About 5–7 hPa (≈0.15–0.21 inHg) | A front or system moving in | Elevated |
| About 8 hPa+ (≈0.24 inHg+) | A strong, fast-moving system | High |
These bands are the same logic Migraine Weather uses to set its Green, Yellow, and Red risk levels, and because sensitivity is personal, the app lets you tighten or loosen them.
Why rate of change beats a single threshold
Two days can both read 1005 hPa, but one is the bottom of a slow, stable low and the other is mid-plunge as a storm slams in. The second is far more likely to trigger an attack. That’s why simply watching for “low pressure” misses the point; the speed of the fall is the signal. A good migraine forecast looks at how many hPa the pressure is changing over a rolling window of hours, not just the current number.
A note on honesty
There’s no universal trigger threshold that applies to everyone, and you should be skeptical of any source that claims one. The 6–10 hPa range is the best-supported general figure, but your personal number could be higher or lower. The only way to find yours is to log attacks against real pressure data over time.
Next
- Barometric Pressure and Migraines: What the Research Actually Says, the mechanism and the studies behind these numbers.
- Why Do I Get a Migraine Before It Rains?, what the drop feels like in real time.
Frequently asked questions
What barometric pressure is "low" for migraines?
Standard sea-level pressure is about 1013 hPa (29.92 inHg). Readings below roughly 1005 hPa (about 29.6 inHg) indicate an active low-pressure system, and the storm range of about 1000–1007 hPa is where weather-triggered attacks tend to cluster. Even so, the drop getting there usually matters more than the number itself.
How fast does pressure have to drop to trigger a migraine?
A fall of around 6 hPa or more over about 6 hours is a commonly used threshold for a meaningful change, with larger and faster drops (8–10 hPa or more) carrying higher risk. Highly sensitive people may react to smaller changes, which is why a good tracker lets you tune the threshold to yourself.
What is the barometric pressure migraine range in inHg?
Normal is about 29.92 inHg. A migraine-relevant drop of 6–10 hPa works out to roughly 0.18–0.30 inHg. Storm-level low pressure is generally below about 29.6 inHg.