Today's barometric pressure in Missoula, a 48-hour pressure chart, and a risk score for weather-triggered migraine and headache, based on pressure drops, humidity, and temperature changes.
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Missoula's mountain valley location in western Montana traps inversions and creates unique pressure patterns. Pacific weather systems funnel through mountain passes, and winter temperature inversions can keep the valley socked in under persistent low pressure.
Worst season for migraines: October through May. Pacific storms funnel through the Clark Fork and Bitterroot valleys from October through May, with November the peak, when 61% of days see a 5 hPa drop. Summer is the calm stretch for pressure, at 21% of days or fewer in each summer month, though wildfire smoke can fill the valley bowl for weeks, which is a separate concern for anyone sensitive to air quality.
Common triggers in Missoula: wildfire smoke inversions trapping hazardous air in the valley, Chinook wind events from the surrounding mountains, Pacific storm fronts channeled through mountain passes. Missoula sits at 3,200 feet at the convergence of five mountain valleys where the Clark Fork, Bitterroot, and Blackfoot rivers meet. This valley-bottom geography makes Missoula notoriously prone to temperature inversions that trap cold air and, during fire season, wildfire smoke that can push air quality into hazardous levels for weeks. The surrounding mountains rise 4,000+ feet above the valley floor, creating dramatic terrain-influenced weather patterns.
Typical pressure: Missoula averages 904 hPa at rest, measured at the city's own elevation rather than corrected to sea level, and storm systems can push readings down to 889 hPa. Swings of 6-12 hPa over 24 hours are common during active weather and fall within the range most associated with pressure-triggered migraines.
2026 index: Missoula ranks #12 of 100 in our 2026 U.S. Migraine Risk Index, where #1 is the most challenging city for weather-driven migraine.
Can Missoula weather trigger migraines?
Yes. Missoula experiences 6-12 hPa barometric pressure swings, and research shows pressure drops are one of the most common migraine triggers. The city's specific patterns include wildfire smoke inversions trapping hazardous air in the valley, Chinook wind events from the surrounding mountains, Pacific storm fronts channeled through mountain passes.
What time of year are migraines worst in Missoula?
In Missoula the most barometrically volatile stretch of the year falls in October through May. That is when weather is most likely to play a part, if weather is a trigger for you at all. See when migraine weather season starts across the U.S.
Is there a barometric pressure headache forecast for Missoula?
This page works as one. Many people call a headache that arrives with a weather change a barometric pressure headache, and this forecast tracks the pressure drops, humidity and temperature swings behind that idea. The score covers the next 24 hours in Missoula and the chart shows the next 48. It is built on migraine research, so treat it as a rough guide for other headaches. A sudden, severe headache needs urgent medical care, whatever the weather.
Your own forecast
This page shows the weather risk for everyone in Missoula. The MigrAid app learns yours. It saves the barometric pressure, humidity and temperature with every migraine you log, shows whether Missoula's swings really line up with your attacks, and alerts you when conditions match your own trigger history.