ECMWF IFS 0.1° wave-height probabilities

GribStream Code: ifswaefprob0p1

About this forecast

ECMWF ensemble probabilities at 0.1° for significant wave height reaching 2, 4, 6 or 8 metres, with global marine guidance to 15 days.

What is ECMWF IFS?

IFS stands for Integrated Forecasting System. Developed by the European Centre for Medium-Range Weather Forecasts (ECMWF) in cooperation with Météo-France, it combines observations through data assimilation and advances a global Earth-system model using physical equations. Its atmosphere, land, ocean and wave components exchange information. These products belong to the short- and medium-range forecast family, extending to 15 days; ECMWF also develops the separate, machine-learning-based AIFS family. ECMWF documentation.

What this product is for

Wave probabilities summarize the IFS wave ensemble for four sea-state thresholds. They help compare marine exposure across routes and operating sites without retrieving every member. A 60% value for the 4 m threshold means a forecast probability of significant wave height at least 4 m at that valid time; it is not the fraction of individual waves exceeding 4 m. ECMWF documentation.

Detail

• Archive begins: 2026-10-20
• Product page: https://www.ecmwf.int/en/forecasts/datasets/open-data
• Key features:
  • Four ECMWF-computed probability fields: significant wave height of at least 2, 4, 6 or 8 m. All are instantaneous percentages (0–100), with no member dimension.
  • The 12-hourly samples describe separate valid times. Assessing whether a limit is exceeded at any time during a voyage requires the member trajectories and an explicit time window.

  • The 0.1° latitude–longitude grid samples the same IFS forecast as the 0.25° products. It has 3,600 × 1,801 points, with about 11 km north–south spacing. ECMWF’s atmospheric model runs at approximately 9 km. Finer output spacing preserves more spatial detail but does not itself establish local accuracy. The 0.1° distribution follows 0.25° by about two hours. ECMWF documentation.

• Resolution: 0.1° · 3600 × 1801
• Temporal coverage: 00 and 12 UTC, every 12 h from +12 to +360 h (15 days).
• Primary uses: Marine hazard screening, offshore operating thresholds and comparing route or site exposure.

Related datasets

• ECMWF IFS Wave ENS 0.1° wave ensemble
• ECMWF IFS Wave 0.1° deterministic wave forecast
• ECMWF IFS ENS 0.1° weather probabilities

Parameters