Air Temperature, Hot Days, Tropical Nights And Icing Days - FUAs

This dataset provides indicators of air temperature, hot days, tropical nights and icing days.

Data sources and methodology

Indicators are estimated using ERA5-Land data. Air temperature indicators correspond to the average annual air temperature at a height of 2 meters. Hot days correspond to the number of days when the maximum temperature exceeds 35°C. Tropical nights correspond to the days when the minimum temperature is above 20°C, and icing days to the number of days when the maximum temperature is below 0°C.

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 (Air temperature, hot days, tropical nights and icing days - 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