We use 15+ independent data sources across climate, air quality, health, economy, geography, and visa requirements. Each source is chosen for coverage, reliability, and update frequency. Here's the complete inventory.
Climate & weather
| Source | What it provides | Coverage |
|---|---|---|
| ERA5 (ECMWF) | Temperature, humidity, wind, radiation, UTCI | Global, hourly, 2015–2024 |
| CHIRPS | Rainfall (satellite + ground gauges) | Global, daily |
| NASA POWER | Solar radiation, surface temperature | Global, daily |
Deep dive: Climate data sources
Air quality
| Source | What it provides | Coverage |
|---|---|---|
| WUSTL PM2.5 | Fine particulate pollution (satellite-derived) | Global, annual |
| OpenAQ | Ground-station air quality (PM2.5, NO2, ozone) | 100+ countries, hourly |
| CAMS (Copernicus) | Air quality forecasts and reanalysis | Global, daily |
Health & economy
| Source | What it provides | Coverage |
|---|---|---|
| OECD | Healthcare, education, economic indicators | 38 member countries |
| Eurostat | Harmonized health, demographic, economic data | EU member states |
| WHO | Global health indicators, life expectancy | 190+ countries |
Geographic & lifestyle
| Source | What it provides | Coverage |
|---|---|---|
| OpenStreetMap | Walkability, transit, green space, POI density | Global, community-maintained |
| GeoNames | City identity, population, coordinates, timezone | 11M+ place names |
| GHSL (EU JRC) | Population density, urban extent (satellite) | Global, high resolution |
Passport & visa
| Source | What it provides | Coverage |
|---|---|---|
| Government visa data | Visa requirements per passport | 190+ countries, daily |
| World Bank | GDP indicators (constant USD) | 190+ countries, annual |
| UNESCO | World Heritage site list | Global, as-updated |
Deep dive: Passport data sources
AI-assisted analysis
| Source | What it provides | Coverage |
|---|---|---|
| LLM extraction | Food scene, nightlife, expat ease, vibe | 500+ cities |
Deep dive: AI-assisted analysis
See it in action
Every metric on a city page cites its source. The explore map covers 29,000+ cities across 90+ features from these datasets.