Today's barometric pressure in Fresno, 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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Fresno's Central Valley location creates a unique weather environment where tule fog in winter brings sustained high-pressure inversions. The valley's agricultural dust and extreme summer heat add environmental triggers beyond barometric pressure alone.
Worst season for migraines: February and March. Winter Pacific storms bring most of Fresno's precipitation and pressure drops, peaking in February, when 34% of days see a 5 hPa drop. No month reaches the 35% of days our index uses for a trigger season. Tule fog can settle over the Central Valley from November through February, with weeks of stagnant, poor-visibility conditions.
Common triggers in Fresno: Tule fog temperature inversions trapping pollutants, winter Pacific storm frontal passages, agricultural dust and particulate air pollution. Fresno sits in the heart of the San Joaquin Valley, a 250-mile trough between the Sierra Nevada and the Coast Ranges. This valley traps air pollution from agriculture and vehicle emissions under persistent winter inversions, creating some of the worst air quality in the nation. The Tule fog that blankets the valley for weeks at a time represents a sustained low-visibility, stagnant-air environment that compounds migraine triggers.
Typical pressure: Fresno averages 1004 hPa at rest, measured at the city's own elevation rather than corrected to sea level, and storm systems can push readings down to 995 hPa. Swings of 3-7 hPa over 24 hours are common during active weather and fall within the range most associated with pressure-triggered migraines.
2026 index: Fresno ranks #95 of 100 in our 2026 U.S. Migraine Risk Index, where #1 is the most challenging city for weather-driven migraine.
Can Fresno weather trigger migraines?
Yes. Fresno experiences 3-7 hPa barometric pressure swings, and research shows pressure drops are one of the most common migraine triggers. The city's specific patterns include Tule fog temperature inversions trapping pollutants, winter Pacific storm frontal passages, agricultural dust and particulate air pollution.
What time of year are migraines worst in Fresno?
In Fresno the most barometrically volatile stretch of the year falls in February and March. 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 Fresno?
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 Fresno 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 Fresno. The MigrAid app learns yours. It saves the barometric pressure, humidity and temperature with every migraine you log, shows whether Fresno's swings really line up with your attacks, and alerts you when conditions match your own trigger history.