# Weather data sources and licences

Open data. Credit required.

## Forecasts (18)

| Source | Provider | Group | Licence | Runs | Covers | Note |
|---|---|---|---|---|---|---|
| NWS grid (`nws`) | NOAA/NWS | NBM | US Government work, public domain | every 15 min | United States | Each place about every 2 h. |
| NBM (`nbm`) | NOAA/NWS MDL | NBM | US Government work, public domain | 01/07/13/19Z | United States |  |
| GFS (`gfs`) | NOAA/NWS NCEP | GFS | US Government work, public domain | 00/06/12/18Z | Worldwide |  |
| AIGFS (`aigfs`) | NOAA/NWS NCEP | GFS | US Government work, public domain | 00/06/12/18Z | Worldwide |  |
| GFS MOS (`mos`) | NOAA/NWS MDL | GFS | US Government work, public domain | 00/12Z | United States |  |
| IFS (`ifs`) | ECMWF | ECMWF | CC BY 4.0 + ECMWF terms | 00/12Z | Worldwide |  |
| AIFS (`aifs`) | ECMWF | ECMWF | CC BY 4.0 + ECMWF terms | 00/06/12/18Z | Worldwide |  |
| ENS (`ens`) | ECMWF via dynamical.org | ECMWF | CC BY 4.0 + ECMWF terms | 00Z | Full-blend places |  |
| MET Norway (`metno`) | MET Norway | ECMWF | CC BY 4.0 (and NLOD 2.0) | every 10 min | Worldwide | Each place about hourly. Inside the Nordics it is its own model group (MEPS). |
| MOSMIX (`mosmix`) | DWD | DWD | CC BY 4.0 | 03/09/15/21Z | Its stations |  |
| ICON (`icon`) | DWD | DWD | CC BY 4.0 | 00/12Z | Worldwide |  |
| GEM (`gem`) | ECCC | CMC | ECCC Open Licence | 00/12Z | Worldwide |  |
| NAEFS (`naefs`) | ECCC and NOAA NCEP | NAEFS | ECCC Data Server End-use Licence v2.1.1 | 00/12Z | Its city list |  |
| SMN (`smn`) | SMN/CONAGUA | SMN | SMN terms (credit; no resale of copies) | 01:00 · 13:00 UTC | Mexico | Credit SMN; no resale of unchanged copies; no mass requests; not an official SMN channel. |
| NBM QMD (`nbmq`) | NOAA/NWS MDL | NBM | US Government work, public domain (NOAA Open Data Dissemination) | 00/12Z | Contiguous US |  |
| HRRR (`hrrr`) | NOAA/NWS NCEP | HRRR | US Government work, public domain (NOAA Open Data Dissemination) | 00/06/12/18Z | Contiguous US |  |
| WPC (`wpc`) | NOAA/NWS WPC | WPC | US Government work, public domain | every 20 min | Contiguous US |  |
| GEFS (`gefs`) | NOAA NCEP via dynamical.org | NCEP | CC BY 4.0 (dynamical.org; NOAA data public domain) | 00Z | Worldwide (day 8 on: US) |  |

## Context (15)

| Source | Provider | Group | Licence | Runs | Covers | Note |
|---|---|---|---|---|---|---|
| METAR (`awc`) | NOAA/NWS AWC | — | US: public domain; non-US: single reports, originator credited | every 5 min | Its stations | Non-US METARs: single latest reports only; the originating service is credited. |
| METAR API (`settle_metar`) | NOAA/NWS AWC | — | US: public domain; non-US: single reports, originator credited | hourly | Settlement stations | Non-US METARs: the originating service is credited. |
| CLI (`settle_poll`) | NOAA/NWS; Hong Kong Observatory | — | US Government work, public domain; HKO: DATA.GOV.HK terms (attribution) | every 10 min | Settlement stations |  |
| CF6 (`cf6`) | NOAA/NWS | — | US Government work, public domain | 15:00 UTC | Settlement stations |  |
| CLM (`clm`) | NOAA/NWS | — | US Government work, public domain | 15:10 UTC | Settlement stations |  |
| HKO daily (`hko_daily`) | Hong Kong Observatory | — | DATA.GOV.HK terms of use (attribution) | 17:30 UTC | Hong Kong |  |
| ACIS daily (`acis_daily`) | NOAA RCC ACIS | — | US Government work, public domain | 15:30 UTC | NYC, Seattle |  |
| Met Office (`ukmo_station`) | Met Office | — | Open Government Licence v3.0 | 09:00 UTC | London (Heathrow) |  |
| Polymarket (`pm_markets`) | Polymarket (gamma API) | — | Venue terms (rules paraphrased, results as facts; no prices) | hourly | Market cities |  |
| MRMS (`mrms`) | NOAA NSSL/NCEP | — | US Government work, public domain (NOAA Open Data Dissemination) | every 10 min | Contiguous US |  |
| NBM NBS (`nbs`) | NOAA/NWS MDL | NBM | US Government work, public domain | 01/07/13/19Z | US market stations |  |
| NWS alerts (`nws_alerts`) | NOAA/NWS | — | US Government work, public domain | every 5 min | United States |  |
| MeteoAlarm (`meteoalarm`) | EUMETNET | — | CC BY 4.0 (MeteoAlarm License) | every 30 min | Europe | Warnings unaltered, with issuer and link. |
| NHC storms (`nhc`) | NOAA/NWS NHC | — | US Government work, public domain | every 30 min | Atlantic, E/C Pacific |  |
| Normals (`acis`) | NOAA RCC ACIS | — | US Government work, public domain | 06:00 UTC | US stations | Each station’s normals once a year. |

## Not used

- Open-Meteo API: Licence is non-commercial
- Met Office DataHub: Needs an API key
- ECMWF ENS direct: 16 MB per time step; we read ENS from dynamical.org
- AIGEFS: An average of models already counted
- NWS observations API: Unreliable; METARs come from AWC
- IEM: An archive of NWS data; we fetch the originals

## Credits

- noaa: Source: NOAA/NWS (US Government work, public domain); NBM/MOS/GFS/AIGFS/HRRR/WPC/MRMS: NOAA NCEP/MDL/NSSL; modified by groundhog (point extraction, local-day max/min, precipitation totals and chances); not endorsed by NOAA
- metno: Data from MET Norway (Locationforecast 2.0), CC BY 4.0 https://creativecommons.org/licenses/by/4.0/ ; modified: local-day max/min, precipitation totals and chances
- dwd: Quelle: Deutscher Wetterdienst (MOSMIX, CC BY 4.0; modified: local-day max/min, precipitation totals and chances)
- eccc: Data Source: Environment and Climate Change Canada (NAEFS: CMC GEPS members) and NOAA NCEP (GEFS members); modified: member daily max/min quantiles, precipitation totals and chances
- ecmwf: Based on data and products of the European Centre for Medium-Range Weather Forecasts (ECMWF); ENS read from dynamical.org's archive. CC BY 4.0 https://creativecommons.org/licenses/by/4.0/ ; modified by groundhog (point extraction, local-day max/min, ensemble quantiles, precipitation totals and chances). ECMWF does not accept any liability whatsoever for any error or omission in the data, their availability, or for any loss or damage arising from their use.
- dyn_gefs: NOAA NWS NCEP GEFS data processed by dynamical.org from NOAA Open Data Dissemination archives. CC BY 4.0 https://creativecommons.org/licenses/by/4.0/ ; modified by groundhog: member precipitation totals, chances and quantiles at points
- smn: Fuente: Servicio Meteorológico Nacional (SMN/CONAGUA), pronóstico por municipio. Not an official SMN channel.
- awc_us: Source: NOAA/NWS Aviation Weather Center (public domain)
- awc_intl: METAR via NOAA Aviation Weather Center; originated by national services
- acis: Source: NOAA Regional Climate Centers, Applied Climate Information System (ACIS; US Government work, public domain)
- hko: Source: Hong Kong Observatory open data via DATA.GOV.HK (attribution required by the DATA.GOV.HK terms of use)
- ukmo: Contains public sector information licensed under the Open Government Licence v3.0 (Met Office historic station data, Heathrow)
- meteoalarm: Source: MeteoAlarm (EUMETNET), warnings issued by national services; CC BY 4.0; text unaltered
- geonames: Place names: GeoNames (geonames.org), CC BY 4.0
- venues: Market rules and results: Kalshi, Polymarket (linked; rules paraphrased by groundhog). Not affiliated with Kalshi or Polymarket.

Free for any use, commercial and trading included, within the rate limit; reuse of the numbers follows each source's licence. groundhog.markets extracts points and builds local-day max/min and ensemble quantiles; providers do not endorse it.

Freshness: https://groundhog.markets/status

Page: https://groundhog.markets/sources