Gas storage forecast · track recordWhat we forecast, and what actually happened
Every past forecast is scored against the reported AGSI+ fill level for its date, reconstructed from committed git history. The numbers are reproducible and were never tuned after the fact.
In brief
Across 7 countries and 22,099 scored forecasts, 68% to 92% of outcomes fell inside the 80% range, depending on the country (scored through 21 October 2026). The mean absolute error was 0.80 to 1.26 percentage points of fill level.
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Questions and answers
- What does coverage mean?
- The share of realised fill levels that fell inside the forecast's P10–P90 band. A calibrated band covers about 80%; much more means the band is wider than it needs to be, much less means it is too narrow.
- Which forecast is scored when the data updates twice a day?
- The first forecast published on each day, as before the evening update existed. The evening build has seen one more day of data, so scoring it would flatter short-range accuracy.
- Why does the forecast start before today?
- AGSI+ publishes each gas day with a delay of one to two days. The model estimates those unpublished days first (the light grey segment in the chart), then forecasts 14 days from today.
- What does the 80% range mean?
- It is the band between the 10th and 90th percentile (P10–P90) of the model's simulated paths: eight out of ten outcomes should fall inside it. Whether they do is checked every day on the track record page.