Best weather models: South Africa and the Southern Ocean
The Ilma catalogue lists 40 weather models that cover the South Africa and the Southern Ocean: 39 global and 1 regional or other. It also lists 14 wave and ocean models. 16 of the weather models have publication times in the catalogue. The finest grid among them is about 4.4 km (SAWS UM).
Fronts pass often and the Southern Ocean can produce very large swell. Near the Cape coast, strong winds can rise quickly, and the Agulhas Current against a swell can make seas steep and dangerous. For passages, global models, wave models and ensembles give the broader picture, and the official marine forecasts and weather routing advice belong alongside them.
Weather models that cover the South Africa and the Southern Ocean
Sorted by grid size, finest first, then by name. This is not a ranking: a finer grid shows more detail but does not make a forecast more accurate. A model is listed when it covers at least half of the area.
| Model | Provider | Resolution | Run cycles |
|---|---|---|---|
| SAWS UM | South African Weather Service | ~2.4 nm | Not catalogued yet |
| ARPEGE | Météo-France | ~3.8 nm | four times a day (00Z, 06Z, 12Z and 18Z) |
| ECMWF ENS | ECMWF | ~4.9 nm | four times a day (00Z, 06Z, 12Z and 18Z) |
| ECMWF IFS | ECMWF | ~4.9 nm | four times a day (00Z, 06Z, 12Z and 18Z) |
| UKMO Global | Met Office | ~5.4 nm | four times a day (00Z, 06Z, 12Z and 18Z) |
| Aurora | Microsoft | ~5.9 nm | Not catalogued yet |
| ACCESS-G | Bureau of Meteorology | ~6.5 nm | Not catalogued yet |
| IMD GFS | India Meteorological Department | ~6.5 nm | Not catalogued yet |
| KIM | KMA | ~6.5 nm | Not catalogued yet |
| NCUM | NCMRWF | ~6.5 nm | Not catalogued yet |
| NEPS-G | NCMRWF | ~6.5 nm | Not catalogued yet |
| GFS | NOAA / NCEP | ~7 nm | four times a day (00Z, 06Z, 12Z and 18Z) |
| ICON | DWD | ~7 nm | four times a day (00Z, 06Z, 12Z and 18Z) |
| JMA GSM | JMA | ~7 nm | four times a day (00Z, 06Z, 12Z and 18Z) |
| GDPS | ECCC | ~8.1 nm | twice a day (00Z and 12Z) |
| NAVGEM | US Navy FNMOC | ~10 nm | Not catalogued yet |
| BAM / MONAN | CPTEC / INPE | ~11 nm | Not catalogued yet |
| MOGREPS-G | Met Office | ~11 nm | four times a day (00Z, 06Z, 12Z and 18Z) |
| CMA-GFS | China Meteorological Administration | ~13 nm | four times a day (00Z, 06Z, 12Z and 18Z) |
| FengWu | Shanghai AI Laboratory | ~13 nm | Not catalogued yet |
| GEFS | NOAA / NCEP | ~13 nm | four times a day (00Z, 06Z, 12Z and 18Z) |
| GEPS | ECCC | ~13 nm | twice a day (00Z and 12Z) |
| ICON-EPS | DWD | ~14 nm | twice a day (00Z and 12Z) |
| JMA GEPS | JMA | ~15 nm | Not catalogued yet |
| AIFS ENS | ECMWF | ~15 nm | four times a day (00Z, 06Z, 12Z and 18Z) |
| ECMWF AIFS | ECMWF | ~15 nm | four times a day (00Z, 06Z, 12Z and 18Z) |
| FourCastNet | NVIDIA | ~15 nm | Not catalogued yet |
| FuXi | Fudan University | ~15 nm | Not catalogued yet |
| GraphCast / GenCast | Google DeepMind | ~15 nm | Not catalogued yet |
| NOAA AI-GFS (AIGFS) | NOAA | ~15 nm | four times a day (00Z, 06Z, 12Z and 18Z) |
| Pangu-Weather | Huawei | ~15 nm | Not catalogued yet |
| ACCESS-GE | Bureau of Meteorology | ~18 nm | Not catalogued yet |
| AICON | DWD | — | Not catalogued yet |
| AIGEFS | NOAA / NCEP | — | Not catalogued yet |
| CMA-GEPS | China Meteorological Administration | — | Not catalogued yet |
| HGEFS | NOAA / NCEP | — | Not catalogued yet |
| NAEFS | NOAA / ECCC | — | Not catalogued yet |
| PEARP (ARPEGE ensemble) | Météo-France | — | Not catalogued yet |
| SL-AV | Hydrometcentre of Russia | — | Not catalogued yet |
| WeatherNext 2 | Google DeepMind | — | Not catalogued yet |
Wave and ocean models
| Model | Provider | Resolution | Run cycles |
|---|---|---|---|
| STOFS / P-ETSS | NOAA | ~0.5 nm | Not catalogued yet |
| DWD GWAM / EWAM / CWAM | DWD | ~2.7 nm | twice a day (00Z and 12Z) |
| Copernicus Global Ocean | Mercator Ocean / Copernicus Marine | ~4.9 nm | Not catalogued yet |
| Navy HYCOM / ESPC | US Navy | ~4.9 nm | Not catalogued yet |
| RTOFS | NOAA / NCEP | ~4.9 nm | once a day (00Z) |
| Met Office WAVEWATCH III | Met Office | ~5.4 nm | Not catalogued yet |
| MFWAM | Météo-France | ~5.4 nm | twice a day (00Z and 12Z) |
| ECMWF WAM | ECMWF | ~7.6 nm | four times a day (00Z, 06Z, 12Z and 18Z) |
| GFS-Wave | NOAA / NCEP | ~13 nm | four times a day (00Z, 06Z, 12Z and 18Z) |
| OSCAR | NOAA / ESR | ~13 nm | Not catalogued yet |
| AUSWAVE | Bureau of Meteorology | — | Not catalogued yet |
| GDWPS | ECCC | — | Not catalogued yet |
| JMA wave models | JMA | — | Not catalogued yet |
| OceanMAPS | Bureau of Meteorology | — | Not catalogued yet |
How to use several models
Compare at least two models, and look at the newest run of each. Where they agree, you can plan with more confidence; where they differ, treat the forecast as uncertain and keep a margin. Read Using several models and Which model for my area? for the method. Official forecasts and warnings come first.
Open the coverage map to check any point, or see all sailing regions.