Rainfall guides
How rainfall is actually measured, and what the numbers can and cannot tell you.
All guides
- Why Your Rain Gauge and a Rainfall App DisagreeRadar rainfall and a backyard gauge measure different things in different places. Here is where the gap comes from, and how to compare them fairly.
- How NOAA's MRMS Rainfall Estimates WorkWhat the Multi-Radar Multi-Sensor system is, how it turns radar echoes and gauge reports into hourly rainfall on a 1 km grid, and what its passes and flags mean.
- How Much Water Is an Inch of Rain?An inch of rain on an acre is about 27,154 gallons. The same inch on a roof, a lawn or a square mile, with the arithmetic shown.
- Gauge-Adjusted, Radar Only, Provisional: What Rainfall Labels MeanEvery Raindex reading carries a label saying how the number was made. What gauge-adjusted, radar only, provisional and no reading mean, and why there is no accuracy percentage.