Data sources and licences
Each section of every page credits its own source. This page adds detail; it does not replace those credits. Terms last checked 2026-11-07.
| Source | Coverage | Licence | Credit | Changes we make | Refresh |
|---|---|---|---|---|---|
| NOAA National Weather Service | United States and territories | U.S. Government work, public domain (no endorsement implied) | Data: NOAA National Weather Service | Units converted for display; periods grouped into days. | Points 24 h; forecasts 15 min; observations 10 min; alerts 2 min. |
| Environment and Climate Change Canada | Canada (ECCC city forecast sites) | ECCC Data Servers End-use Licence | Data Source: Environment and Climate Change Canada | Units converted for display; text reformatted. Alert wording is preserved. | City site lookup 24 h; city weather 10 min. Stay well below 86,400 requests/day. |
| MET Norway (Norwegian Meteorological Institute) | Worldwide point forecasts | CC BY 4.0 | Weather forecast from MET Norway, licensed under CC BY 4.0 | Converted units; hourly and 6-hour steps aggregated by us into local calendar days; current conditions estimated from the nearest forecast step. | Per Expires header (typically ~30 min), conditional requests. |
| SunCalc 1.9.0 | Worldwide (sea-level horizon) | BSD-2-Clause, Copyright (c) 2014 Vladimir Agafonkin | Sun times calculated with SunCalc (BSD-2-Clause) | Calculated locally for the location and civil date. | Calculated on demand. |
| ExchangeRate-API (Open Access) | Major world currencies | Open Access terms (attribution required; no redistribution) | Rates By Exchange Rate API | Single converted amounts only; no rate tables or exports. | Once per provider update (daily). |
| UN DESA World Urbanization Prospects 2025 | 164 urban areas in North America, Europe (excl. Russia), East Asia and Oceania | CC BY 3.0 IGO | City list and populations: UN DESA, World Urbanization Prospects 2025 (File 21) | Filtered to urban areas of 1 million+ in selected regions; names shortened for display; province/state and time zone added from GeoNames-based data. | Annual review; edition frozen for launch. |
No agency logos are used, and no endorsement is implied. MET Norway data is used under CC BY 4.0; we do not use Yr branding.
Weather condition icons and companion artwork are original ChowChow Labs artwork.