Shipping companies and recreational sailors alike know just how important it is to have an accurate marine weather forecast. Offshore weather can change rapidly; for big shipping vessels, a lack of understanding of marine weather can impact 80% of the ship's performance.
[Read more: How Maritime Weather Forecasting Minimizes Risks in Shipping Operations]
Because conditions can change so quickly, it’s critical that ships receive timely and accurate weather forecasts. How do ship captains receive weather forecasts? How is offshore weather data collected and transmitted in a usable report? This article will dive into the intricacies of collecting data, creating weather reports, and transmitting those reports to ships at sea in real-time.
Who creates marine weather forecasts?
First, let’s examine who is in charge of collecting weather forecasting data and creating reports that ships can use to navigate safely. There are various organizations located around the world that are responsible for tracking maritime weather. The National Weather Service (NWS) branch of the NOAA in the US is one; the Maritime & Coastguard Agency (MCA) branch of the Met Office in the UK is another.
How do all these different bodies work together? The World Meteorological Organization is an international organization that provides guidelines for these agencies and offers information for international waters. The WMO’s World Weather Watch networks observing stations to national, regional, and global weather prediction centers.
“The World Weather Watch collects meteorological, climatological, hydrological and oceanographic data from over 15 satellites, 100 moored buoys, 600 drifting buoys, 3,000 aircraft, 7,300 ships and some 10,000 land-based observation stations,” reports the WMO. “This data has to be comparable and up to standards in order to be usable by the prediction centers in the numerical weather prediction models that produce daily weather forecasts and early warnings for natural hazards such as hurricanes.”
Shipping companies and recreational vessels can choose to get their weather forecast from any of these bodies; NOAA, for instance, offers maritime weather forecasts via email or online. Private companies, too, provide weather forecasting services — more on that in a minute.
How do ships receive the weather forecast?
Ships that travel close to the coast are often able to receive radio transmissions from NOAA and its international counterparts. NOAA also offers its maritime weather forecast via email. For those traveling farther afield, or looking for real-time weather forecasts, there are six general methods of getting weather aboard. These methods include:
- A single side band (SSB) receiver
- An SSB transceiver
- A satellite hotspot
- A black box satellite weather device
- A satellite telephone
- A satellite messenger
Each method has its pros and cons; ships must weigh factors such as portability, cost, and ease of use when selecting their transmission tool.

What works for a small sailboat won’t likely be suitable for a massive shipping vessel. And, more importantly, a transmission tool is only as good as the data it provides.
What information is provided in a weather forecast?
Because many parts of the ocean are so remote, international weather organizations are limited in what data points they can collect. The ocean surface measures somewhere around 140 million sq miles. Most parts are too remote for wide-band communications. Saltwater, violent storms, and breaking waves make for difficult conditions for technology that would collect and transmit data for better forecasts.
Wave data, which is often excluded from marine weather forecasts, is an important metric of meteorology that affects ocean activities and coastal dynamics. Wave strength is correlated with wind speed on the ocean surface. Feeding real-time sensor data into a weather model yields more accurate storm predictions.
Scientists are watching waves worldwide to develop better global weather model forecasts that account for a variety of novel variables.
Improving offshore weather forecasting
While the WMO, Met, and NWS have access to more data sources than ever, marine weather forecasts are still difficult to get right. The weather models in use by NOAA, ECMWF, and others are remarkably accurate. However, international weather organizations struggle with accessibility, data quantity, and data quality.
[Read more: Why Marine Weather Forecasts Are So Inaccurate - And How To Improve Them]
These are issues that nonprofit organizations and private companies like IBM hope to solve. Sofar Ocean is leading the charge with its open and accessible marine data services that provide observation, forecast, and hindcast weather data from Sofar’s global Spotter network.
Sofar Ocean uses real-time observation data from the world’s largest network of connected open ocean buoys. This data feeds into forecasts that are up to 50% more accurate than NOAA and ECMWF, Europe’s weather forecasting service. And, because the API is designed for the cloud, real-time weather is always available, continuously upgraded, and can be customized depending on the ship and the route.
Sofar Ocean's network of Spotter buoys, with numbers approaching triple digits by the end of the year, collects data on waves, wind, currents, and sea-surface temperature. This helps ship captains make smarter decisions to save on fuel, optimize routing, and deliver on time.
To learn more about maritime weather forecasting, visit the Sofar Ocean blog.