In addition to the General sites, many of the national meteorological services listed have sections on their sites dealing with global weather, sea conditions, databases and alike.
Africa
Australasia
Europe
European Centre for Medium-Range Weather Forecasts (ECMWF) develops numerical methods for medium-range weather forecasting; prepares on a regular basis, medium-range weather forecasts for distribution to the meteorological services of the Member States; undertakes research to improve forecasts, and compiles meteorological data.
General
HF-Fax is a broad based site with a substantial listing of meteorological services, bureaus and research centres.
World Meteorological Organization is an United Nations agency involved with the state and behaviour of the Earth’s atmosphere, its interaction with the oceans, the climate it produces and the resulting distribution of water resources.
USA