Atmospheric pressure is the force exerted on the Earth's surface by the weight of the atmosphere above. The air exerts 1.033 kg of pressure on every square centimeter of the surface.

The standard atmospheric pressure is 760 mmHg. This pressure is considered the most comfortable for people, but standard pressure varies with altitude: the higher the altitude, the lower the pressure.

Atmospheric pressure is measured using a special instrument called a barometer, which can be mercury, liquid, mechanical, or electronic. Millimeters of mercury (mmHg) is the standard unit of measurement for atmospheric pressure, but it is also commonly measured in hectopascals (hPa).

Atmospheric pressure varies with the formation and movement of large air masses that directly influence the weather. Low-pressure air vortices, known as cyclones, can have a central low-pressure area and a radius extending for thousands of kilometers.

The atmospheric pressure in Reis today is 670 mmHg. The pressure forecast for tomorrow is 671 mmHg. Pressure in Reis: normal.