ECMWF's AIFS Single goes operational with 5–15% lower errors

ECMWF's AIFS Single became operational 25 February 2025; ECMWF reports 5–15% lower errors than IFS; no specific event documented.

AI system

System

ECMWF Artificial Intelligence Forecasting System (AIFS)

Model

AIFS Single v1.

Release

AIFS Single v1.

Application developer

ECMWF

Role

AIFS generated weather forecasts.

Configuration

The reported forecasts used AIFS Single v1, operational from 25 February 2025.

Inputs and outputs

Not assessed

Autonomy

Not assessed

Workflow

Operational twice-daily AIFS Single runs initialized from ECMWF analyses. ECMWF's standard headline-score and tropical cyclone verification against the IFS.

Human oversight

Not assessed

Relation to AI

ECMWF's verification compares AIFS directly with the IFS. The only non-ECMWF cited source (NWS Q&A) confirms NHC evaluated ECMWF's AI system in 2025 but states no performance result. ECMWF is both the developer and the deployer, so its evaluations are the body reporting on its own system.

AI contribution

ECMWF's verification compares AIFS directly with the IFS. The only non-ECMWF cited source (NWS Q&A) confirms NHC evaluated ECMWF's AI system in 2025 but states no performance result. ECMWF is both the developer and the deployer, so its evaluations are the body reporting on its own system.

Benefits

Outcome identifiers

Not assessed

Benefit

5–15% lower errors than IFS

Category

Improved Task Accuracy

Status

Not assessed

Beneficiary groups

People. Organizations. Society.

Beneficiaries

Not assessed

Reach

Not assessed

Distribution and access

Not assessed

Duration

Not assessed

Expected?

Yes

Costs and harms

Not assessed

Measurement

Studies

Not assessed

Study design

Not assessed

Measurement

Not assessed

Setting and sample

Not assessed

Measures

5–15% lower errors than IFS

Comparison

ECMWF's physics-based Integrated Forecasting System (IFS)

Results

Result: errors 5 to 15% lower in the medium range (out to 15 days).

Additional value from AI

Not assessed

Limitations

Not assessed

Denominators

Not assessed

Materials for replication

Not assessed

Money

Kind of value

Not assessed

Amount

Not assessed

Currency and prices

Not assessed

Period and unit

Not assessed

Realization

Not assessed

Recipients and payers

Not assessed

Gross or net

Not assessed

Included costs

Not assessed

Comparison

Not assessed

Method

Not assessed

Return and payback

Not assessed

People and places

Participants

Developer: ECMWF. Operator: ECMWF.

Jurisdictions

Benefit: Reading, United Kingdom. Developer: United Kingdom. Operator: United Kingdom.

Ownership and control

Not assessed

Dependencies

Not assessed

Cross-border connections

Not assessed

Geopolitical implications

Not assessed

Follow-up

Conditions for replication

Intensity under-prediction persists per ECMWF and the AIFS-TC preprint. No ECMWF-documented named event where AIFS beat the IFS was found. Event-level superiority remains unverified.

Replication attempts

2 follow-up entries. Benefit recurred: 2.

Later findings

1 July 2025. ECMWF launched the ensemble version, AIFS-ENS, operationally on 1 July 2025, and its 2025 evaluation (May 2026) reports both AIFS Single and AIFS ENS beating the IFS on most parameters.

Availability

Not assessed

Institutional decision

Not assessed

Grounds

Not assessed

Action and result

Not assessed

Success criterion

Not assessed

Evidence

Source numbers

AIBD-0143-source-0001–0006

Citations

Numbered references below.

Language

Not assessed

Source relationships

Developer, Independent

Original evidence

Not assessed

Access and versions

Not assessed

Supported findings

Not assessed

Evidence strength

Not assessed

Missing evidence

Not assessed

Grades

Assessed benefits

People. Organizations. Society.

Depth

Not assessed

Reasons

People: Aggregate skill statistics, no discrete event. Organizations: Aggregate skill statistics, no discrete event. Society: Aggregate skill statistics, no discrete event.

Observed or intended

Not assessed

Rubric

Not assessed

Assessor and date

Not assessed

Alternative assessments

Not assessed

Fill

Independently studied

Entry details

Kind

Not assessed

Field

Weather forecasting. Public-sector meteorological service.

Purpose

Operational data-driven global medium-range weather forecasting at ECMWF, run alongside the physics-based IFS.

Dates

Date basis unassessed: 2025 (precision unassessed). Updated: 21 October 2026.

Stage

Not assessed

Version

SHA-256: 9e2e95a24742…

References

Other identifiers

Not assessed

Category mappings

Not assessed

Brief

Not assessed

Revisions

5 revisions. Latest: 21 October 2026.

Sources

  1. Report Developer

    Haiden, T., Chevallier, M. (2026). Forecast performance 2025. ECMWF Newsletter No. 187, May 2026.

  2. Report Independent author

    National Weather Service (n.d.). AI in Hurricane Forecasting at the National Hurricane Center: A Q&A with NHC Science Operation Officer Wallace Hogsett. NOAA/NWS.

  3. Preprint Developer

    Allen, A., Bruinsma, W. P., Maier-Gerber, M., Cook, H., Chantry, M., Turner, R. E. (2026). AIFS-TC: A simple correction competitive with the operational frontier for tropical cyclone intensity forecasting. arXiv:2608.09959.

  4. Press release Developer

    ECMWF (2025). ECMWF's AI forecasts become operational. ECMWF news, 25 February 2025.

  5. Press release Developer

    ECMWF (2026). 2025 forecast evaluation met with positive feedback. ECMWF news, 8 May 2026.

  6. Other Developer

    ECMWF Forecast User wiki (2025). Severe Event Catalogue: 202501 - Windstorm - Eowyn.