What is the SI unit of pressure?

The SI unit of pressure is the pascal, which is defined as one newton per square meter. It serves as the foundational unit in the International System of Units (SI) for measuring pressure. The pascal is widely utilized in various scientific and engineering disciplines to quantify the amount of force applied over a given area, making it a fundamental concept in fields such as meteorology, where atmospheric pressure plays a crucial role in weather patterns and systems.

While other units like millibar, hectopascal, and atmosphere are commonly used in meteorological contexts and have their own significance within specific applications or traditions, they can be converted to pascals. For instance, one millibar is equal to 100 pascals and one hectopascal also equals 100 pascals. The atmosphere is a unit of pressure that is defined as being equal to 101,325 pascals. However, since the question asks for the SI unit of pressure, the pascal is the correct answer as it is the base unit defined within the metric system.