Submitting Forecasts

During the AI Weather Quest Competition Phase, participating teams are challenged to submit real-time forecasts every week. 

New to weather forecasting? No problem! The competition is designed to welcome participants with diverse expertise, including those entirely new to meteorology. 

To get started:

1. Read the detailed information below to understand the forecast requirements, workflow, and tools you will need to participate.
2. Familiarise yourself with the evaluation system to fully understand forecast submission requirements.
3. Join the AI Weather Quest forum to stay updated on the competition (including potential updates regarding requirements, tools, resources, evaluation, etc.), ask questions, and connect with fellow participants.

Join the Quest

Which forecasts to submit?

Teams are challenged to submit weekly, real-time sub-seasonal forecasts of at least one of the following variables:

For temperature and pressure forecasts, teams are required to produce weekly averages, which will be evaluated against weekly means calculated using six-hourly data (00, 06, 12 and 18 UTC). For precipitation forecasts, the focus is on weekly accumulations, which will be compared against corresponding reanalysis totals (see evaluation for more details).

Forecasts should include global, quintile probabilities at a 1.5-degree latitude/longitude resolution for one of the following lead times (inclusive):

• Days 19 to 25 
• Days 26 to 32

To ensure flexibility for AI/ML innovation participants can:

• Submit up to six forecasted variables per AI model (three variables × two lead times).
• Use up to three different AI/ML models, allowing a maximum of 18 submissions per team each week.
• Develop AI/ML models using any observational or forecast datasets which may include ECMWF-supported datasets.
• Develop AI/ML models using any programming language.

Submissions are welcome from various types of ML/AI models, including (but not limited to):

• Models that post-process numerical weather prediction data. 
• Machine-learning based models specifically designed for weather prediction. 
• Statistical models that focus primarily on generating quintile probabilities. 
• Hybrid models that combine physical simulations with machine-learning techniques. 

Innovation is at the heart of this competition. Participants are encouraged to experiment with diverse architectures and methodologies to improve forecast skill and reliability. While competitors should only make minimal model changes during each competitive period, they may refine their models between periods, incorporating lessons learned and keeping pace with rapid advancements in AI and ML.

To promote transparency, forecasts will be displayed on an ECMWF-hosted sub-seasonal AI forecasting portal following the closure of the submission window, with submitted data made publicly accessible after each 13-week competitive period.

Forecast submission schedule

The AI Weather Quest focuses on sub-seasonal forecasts initialised every Thursday and adheres to a structured submission schedule. This enables direct comparison between sub-seasonal forecasts generated by AI/ML models and those based on traditional dynamical models.

The key dates in the forecast submission schedule are as follows (first competition week used as an example):

• Day 1: Forecast initialisation date (Thursday 14th August 2025 00:00 UTC).
  

  Participants may use any data with a timestamp strictly prior to Thursday 00 UTC to initialise their models, regardless of when the data becomes available. The four-day submission window allows participants to process initial data with relatively long latency (e.g. dynamical sub-seasonal forecast data which has a two-day delay) and provides additional time for those with limited computational resource to submit their forecasts.

• End of day 4: Forecast submission closes (Sunday 17th August 2025 23:59 UTC).
  A four-day submission window accommodates for varying resource capabilities.
• Days 19 to 25: First forecast window (Monday 1st September 2025 00:00 UTC to Sunday 7th September 18:00 UTC (tas, mslp)/Monday 8th September 00:00 UTC (pr))
• Days 26 to 32: Second forecast window (Monday 8th September 2025 00:00 to Sunday 14th September 18:00 UTC (tas, mslp)/Monday 15th September 00:00 UTC (pr))
• Day 37: Forecast evaluation publication (Friday 19th September 2025 UTC) 

Access the full forecast schedule dates for both the testing and competitive periods.

How to submit your forecasts

Forecasts must be submitted using the AI-WQ-package, a Python package designed to ensure compatibility with the evaluation system and visualisation portal. Detailed installation instructions and user guidance for all modules can be found in the official package documentation. 

The following steps provide a summary of the submission process using the forecast_submission.py module included in the package:

• Use the AI_WQ_create_empty_dataarray function to generate an empty xarray.DataArray.
• Populate the array with forecast probabilities.
• Submit using the AI_WQ_forecast_submission function.

Please note, several checks on filename and data characteristics are taken before accepting submissions. A full list of these checks is available in the official package documentation.

Participants can use the plotting_forecast.py module to generate global visualisations of forecast probabilities, helping them perform personal quality control.

You will need your forecast submission password, provided in your registration email upon joining the Quest, to complete the forecast submission.

Join the Quest

Issues or questions?

We encourage participants to promptly report any technical concerns or issues. Please reach out to the competition organisers through the following channels: