Barometric Pressure in O'Fallon, United States 
1018.9 hPa
15.3 ℃
87%
0.58 m/s
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The average pressure in O'Fallon, Missouri, United States today is , which is considered normal. Pressure is trending falling.
Weather prediction: Occasional rain, worsening
Rapid Pressure Changes
Rapid pressure changes detected in O'Fallon, often a sign of approaching weather shifts. See the forecast chart or get pressure alerts.
- Rapid Fall : ()
- Rapid Rise : ()
The daily total fluctuation in pressure in O'Fallon is , with a low of and a high of .
Forecast
Hourly Pressure Trends
Track the barometric pressure in O'Fallon hour by hour across the next 6 hourly readings.
O'Fallon's air pressure changes with weather. Low pressure brings rain and storms, while high pressure brings clear skies.
Its location in the Midwest, near mountains, affects air pressure.
Air from the west coast rises over mountains, cools, and loses moisture before reaching O'Fallon.
In spring and summer, low pressure dominates, bringing thunderstorms.
In fall and winter, high pressure prevails, bringing cold but clear weather.
O'Fallon has a humid continental climate with big pressure changes between seasons.
This climate brings cold winters with low pressure and warm summers with high pressure.
Weather fronts from Canada and the Gulf of Mexico meet in O'Fallon, changing air pressure.
Pressure changes cause different weather, like storms or clear skies.