Precipitation - FUAs

This dataset provides indicators of total precipitation and extreme precipitation days in Functional Urban Areas (FUAs).

Data sources and methodology

The indicators use ERA5-Land data. Total precipitation is the sum of all liquid and frozen water—such as rain and snow—that reaches the Earth's surface each year. It excludes fog, dew, and any precipitation that evaporates before reaching the ground. Extreme precipitation days are defined as days with more than 20 mm of total precipitation.

Defining FUAs and cities

The OECD, in cooperation with the EU, has developed a harmonised definition of functional urban areas (FUAs) to capture the economic and functional reach of cities based on daily commuting patterns (OECD, 2012). FUAs consist of:

1. A city – defined by urban centres in the degree of urbanisation, adapted to the closest local administrative units to define a city.
2. A commuting zone – including all local areas where at least 15% of employed residents work in the city.

The delineation process includes:

• Assigning municipalities surrounded by a single FUA to that FUA.
• Excluding non-contiguous municipalities.

The definition identifies 1 285 FUAs and 1 402 cities in all OECD member countries except Costa Rica and three accession countries.

Cite this dataset

OECD Regions, cities and local areas database (Precipitations - FUAs), http://oe.cd/geostats

Further information

• OECD Local Data Portal
• OECD Regions and Cities at a Glance

For questions and/or comments, please email CitiesStat@oecd.org