Today's barometric pressure in San Jose, 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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San Jose benefits from the Santa Clara Valley's sheltered geography, but atmospheric rivers in winter bring sustained pressure drops. The Bay Area's microclimates mean conditions can vary significantly within a short drive.
Worst season for migraines: February. Winter Pacific storms push through the Santa Clara Valley bringing the bulk of San Jose's annual pressure variability. The valley's sheltered position between the Santa Cruz Mountains and the Diablo Range moderates many systems, but atmospheric rivers can still deliver sharp drops.
Common triggers in San Jose: Pacific atmospheric river events, temperature inversions trapping poor air quality, rapid post-storm clearing and pressure rebounds. San Jose sits at the southern end of San Francisco Bay in a broad valley that traps warm air and pollution during temperature inversions. The Santa Cruz Mountains block some marine influence from the west, giving San Jose warmer, drier conditions than San Francisco just 50 miles north, but also trapping particulate matter that acts as a secondary migraine trigger.
Typical pressure: San Jose averages 1015 hPa at rest, measured at the city's own elevation rather than corrected to sea level, and storm systems can push readings down to 1002 hPa. Swings of 4-8 hPa over 24 hours are common during active weather and fall within the range most associated with pressure-triggered migraines.
2026 index: San Jose ranks #92 of 100 in our 2026 U.S. Migraine Risk Index, where #1 is the most challenging city for weather-driven migraine.
Can San Jose weather trigger migraines?
Yes. San Jose experiences 4-8 hPa barometric pressure swings, and research shows pressure drops are one of the most common migraine triggers. The city's specific patterns include Pacific atmospheric river events, temperature inversions trapping poor air quality, rapid post-storm clearing and pressure rebounds.
What time of year are migraines worst in San Jose?
In San Jose the most barometrically volatile stretch of the year falls in February. 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 San Jose?
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 San Jose 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 San Jose. The MigrAid app learns yours. It saves the barometric pressure, humidity and temperature with every migraine you log, shows whether San Jose's swings really line up with your attacks, and alerts you when conditions match your own trigger history.