When Is Rainfall Measured?

Observations. Daily rainfall is nominally measured each day at 9am local time. However there are a number of sites which report 48 or 72 hour totals (or occasionally longer) over weekends if the observer is unable to be present. These are known as accumulated observations.

On what basis rainfall is measured?

The most common rainfall measurement is the total rainfall depth during a given period, expressed in millimeters (mm). For instance, we might want to know how many millimeters of rain fell over the course of 1 h, 1 day, 1 month, or 1 year.

Where is rainfall measured?

A rain gauge is really just a cylinder that catches rain. If an inch collects in the cylinder, it means an inch of rain has fallen. It's that simple. Most standard rain gauges have a wide funnel leading into the cylinder and are calibrated so that one-tenth of an inch of rain measures one inch when it collects inside.