A three-day rainfall measurement covers a single sustained rain event or a series of shorter events over a three-day period. Such measurements help us understand and prepare for flooding or rain-induced slips that could cause damage.
Further information can be found in:
Tait, A, Macara, G, & Paul, V. (2014) Preparation of climate datasets for the 2015 Environmental Synthesis Report: Temperature, Rainfall, Wind, Sunshine and Soil Moisture. Prepared for Ministry for the Environment. Available at https://data.mfe.govt.nz/x/Fwn9AL on the Ministry for the Environment dataservice (https://data.mfe.govt.nz/).
This dataset relates to the "Annual maximum three-day rainfall" measure on the Environmental Indicators, Te taiao Aotearoa website.