Stratus clouds produce a drizzle or light mist, never an honest rain. Most often resembling a cotton ball there are many types of cumulus clouds to be aware of. But as I said this is not a meteorology course and you are not meteorology majors, so we will only discuss them in brief using the chart below. No seriously it is of extreme importance that a boater have some knowledge of how to measure atmospheric pressure. Because almost every aspect of weather is affected by it in some way.
Atmospheric pressure is measured by a device known as a barometer.
There are two common types of barometers. The first is a mercurial barometer, which measures atmospheric pressure by balancing a column of mercury against the weight of the air. The second and most commonly used by boaters is the aneroid barometer. This type of barometer measures the amount of change in the atmospheric pressure. The barometer does this by using the atmospheric pressure to bend a metallic surface connected to a pointer on a scale.