There are several methods to measure rainfall, including:

Rain gauge: This is the most common and simplest method for measuring rainfall. It consists of a cylindrical container with a funnel that collects and measures the amount of rain.

Tipping bucket rain gauge: This type of gauge uses a mechanism that tips over when a certain amount of rainfall has accumulated, which helps to measure rainfall more accurately.

Optical rain gauge: This type of gauge uses a laser to measure the amount of rainfall by detecting the changes in light transmission through the rain.

Disdrometer: This measures the size, shape, and velocity of raindrops to determine the amount of rainfall.

Radar: Weather radars can detect the presence of rain and estimate its intensity by measuring the reflectivity of the radar signal.

Satellite: Rainfall can be measured using satellite imagery, which can provide a large-scale view of rainfall patterns and intensity over a given area.