Today's barometric pressure in Green Bay, 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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Green Bay's position at the base of a large Lake Michigan bay amplifies lake-effect weather. The city's northerly latitude and Great Lakes exposure create extended periods of low pressure in winter that coincide with the most active migraine seasons.
Worst season for migraines: October through June. Green Bay's position at the southern tip of the bay of Green Bay on Lake Michigan creates dual lake-effect impacts from both the bay and the main lake. Winter storms bring persistent cloud cover, lake-effect snow, and rapid pressure changes as Arctic air masses sweep across the water.
Common triggers in Green Bay: dual lake-effect from Green Bay and Lake Michigan, polar vortex extreme cold events, persistent winter overcast and light deprivation. Green Bay sits where the Fox River empties into the bay of Green Bay, a long arm of Lake Michigan that creates its own lake-effect patterns. The bay freezes earlier than the main lake, changing the city's weather regime mid-winter as ice coverage modifies moisture flux. The flat Fox River valley channels winds directly from the bay into the city, and the transition from frozen to open water in spring creates additional atmospheric instability.
Typical pressure: Green Bay averages 994 hPa at rest, measured at the city's own elevation rather than corrected to sea level, and storm systems can push readings down to 975 hPa. Swings of 8-18 hPa over 24 hours are common during active weather and fall within the range most associated with pressure-triggered migraines.
2026 index: Green Bay ranks #13 of 100 in our 2026 U.S. Migraine Risk Index, where #1 is the most challenging city for weather-driven migraine.
Can Green Bay weather trigger migraines?
Yes. Green Bay experiences 8-18 hPa barometric pressure swings, and research shows pressure drops are one of the most common migraine triggers. The city's specific patterns include dual lake-effect from Green Bay and Lake Michigan, polar vortex extreme cold events, persistent winter overcast and light deprivation.
What time of year are migraines worst in Green Bay?
In Green Bay the most barometrically volatile stretch of the year falls in October through June. 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 Green Bay?
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 Green Bay 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 Green Bay. The MigrAid app learns yours. It saves the barometric pressure, humidity and temperature with every migraine you log, shows whether Green Bay's swings really line up with your attacks, and alerts you when conditions match your own trigger history.