Why Atmospheric Pressure Matters

While we often focus on temperature, rain, and wind, another crucial element that we may not think we experience, but which significantly impacts our weather, is atmospheric pressure. Understanding atmospheric pressure provides deeper insight into weather patterns and can be vital in a wide range of applications.

What is Atmospheric Pressure?

Atmospheric pressure (or barometric pressure) is the force exerted by the weight of the air in Earth's atmosphere. Imagine a column of air extending from the Earth's surface to the top of the atmosphere – that column's weight presses down on everything below. This pressure is measured in units like hectopascals (hPa), millibars (mb), or inches of mercury (inHg).

Atmospheric pressure varies with altitude, temperature, and weather systems. Average sea-level pressure is around 1013.25 hPa (or 29.92 inHg). The higher in the atmosphere we travel, the lower the pressure.

High and Low Pressure: Driving Weather Patterns

The variations in atmospheric pressure can drive our weather. As air moves from high to low pressure, wind is created. The greater the pressure difference, the stronger the wind.

Atmospheric pressure can exist in various systems:

• High-Pressure Systems (Anticyclones): Sinking air warms and dries, leading to clear skies, calm winds, and stable weather. High-pressure systems are associated with sunny days. Air circulates clockwise around them in the Northern Hemisphere, and counter-clockwise in the Southern Hemisphere.

• Low-Pressure Systems (Cyclones): Rising air cools, causing water vapor to condense, forming clouds and potentially precipitation. Low-pressure systems are associated with cloudy skies, wind, and unsettled weather. Air circulates counter-clockwise around them in the Northern Hemisphere, and clockwise in the Southern Hemisphere.

How Atmospheric Pressure Affects Us

The changes in atmospheric pressure can have a number of different effects on our everyday lives:

• Human Body: Some people are sensitive to pressure changes, experiencing headaches, joint pain, or sinus issues.

• Angling: Barometric pressure changes can affect fish behavior. Many anglers believe fish are more active during changing pressure, especially a falling barometer.

• Adventurers: Even the boiling point of water is affected by atmospheric pressure, being lower at higher altitudes, lengthening cooking times. Something experienced by those intrepid mountaineers who scale the world’s highest peaks.

OpenWeather and Atmospheric Pressure

OpenWeather provides detailed atmospheric pressure data in our forecasts, APIs, and maps such as the OpenWeather Weather maps 2.0 with 1-hour step. You can track pressure changes and use this information, along with other parameters, to gain a more complete understanding of the weather. Atmospheric pressure is a hidden force that plays a significant role in shaping our weather, as well as our daily lives.