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Capitals of the world
Capital data: sources and method
The 172 capital pages rest on five open sources: DailyGeo's own game data, ERA5 reanalysis for climate, the Copernicus DEM for elevation, the World Bank for economics, and Wikidata for founding dates. No figure is estimated: a field with no source is shown as not reported.
This page exists so that any figure on a capital page can be checked at its source. For each field it gives the origin, the year it refers to, and, where a number is not taken straight from a source, the computation behind it.
Where each figure comes from
| Figure | Source | Period |
|---|---|---|
| City population, coordinates | DailyGeo game data | urban area |
| Temperature, rainfall | ERA5 reanalysis via Open-Meteo | 2015 to 2024 |
| Elevation | Copernicus DEM via Open-Meteo | terrain model |
| Time zone | Resolved from the coordinates via Open-Meteo | current |
| GDP, GDP per capita | World Bank (GDP, per capita) | latest year |
| Country population | World Bank (series) | latest year |
| Life expectancy, internet use | World Bank (life, internet) | latest year |
| Big Mac price | The Economist's Big Mac index (big-mac-data) | latest release |
| Founding date | Wikidata | earliest recorded claim |
| Country list | the game's 172 countries, against the UN member states | current |
What is computed rather than copied
- Monthly normals: ERA5 daily means are pulled for ten full years and then averaged per month. A page shows a month only if all ten years cover it.
- Winter and summer: December to February and June to August, swapped in the southern hemisphere. Between the tropics the pages name the months instead of claiming a season, because there the warmer half of the year is not the calendar summer.
- Distances: great-circle distance between city centres, the same measure the game reports.
- Rankings: world and continental rank by city population. The heavy concentration among the largest capitals is not an artefact of the sample: city sizes follow a power law, first described in these terms by Gabaix, X. (1999).
- Superlatives: a page claims a record only if the capital places in the top three of an ordering, and a world record replaces the matching continental one.
What this data does not cover
- The Big Mac index covers 54 of the 172 countries. The rest show no price rather than an estimate.
- Founding dates exist for 130 capitals of 172, and some of those refer to the first occupation of the site rather than the founding of a city.
- Population is urban-area wide and elevation is a single point. The two do not combine: no density is published, because dividing an urban-area population by a commune's area gives a figure that is simply wrong.
- Elevation is the terrain height at the city's coordinates, not the official elevation of a municipal reference point. The two differ by tens of metres in hilly cities.
- The economic figures are national, not municipal. A country's GDP per capita does not describe living standards in its capital.
- The data is not fixed. Every field carries its source's year, and a fresh collection can move a ranking.
Sources
- Hersbach, H., et al. (2020). The ERA5 global reanalysis. Quarterly Journal of the Royal Meteorological Society.
- Gabaix, X. (1999). Zipf's Law for Cities: An Explanation. The Quarterly Journal of Economics.
- World Bank, World Development Indicators: GDP, GDP per capita, population, life expectancy, internet users.
- United Nations, World Urbanization Prospects, for urban population framing, and UN member states.
- The Economist, Big Mac index, published dataset: big-mac-data.
- Wikidata, for founding dates and localized names.
The short answer
DailyGeo's capital pages use ERA5 for climate (ten-year means, 2015 to 2024), the Copernicus DEM for elevation, the World Bank for economics and Wikidata for founding dates. Missing fields are flagged rather than estimated.
Turn the reading into recall. A new capital and country are waiting today.
Play today's DailyGeo puzzleFrequently asked questions
Where do the temperatures come from?
From the Copernicus programme's ERA5 reanalysis, retrieved through Open-Meteo. Each monthly value is the mean of daily means across ten full years, 2015 to 2024, rather than a single year's reading.
Are these figures up to date?
Every page names the source of each field, and the World Bank series carry their latest reported year. Climate is a ten-year mean and therefore stable, while the economic figures move year to year.
Why is no population density given?
Because the population used is urban-area wide while the available area is the commune's. Their ratio would be wrong by orders of magnitude, so no density is published at all.
Can this data be reused?
Each source carries its own licence: ERA5 and the Copernicus DEM fall under the Copernicus terms, the World Bank series under its open data licence, and Wikidata is public domain (CC0). Cite the original source rather than this page.
Keep learning
- Capitals of the world: the full list by continent
Every capital in DailyGeo's atlas, grouped by continent, with population, elevation and winter and summer temperatures, each linking to its own data page.