---
title: ECMWF ensemble (ENS)
summary: The same IFS run many times from slightly different starts: the spread between members is the forecast's uncertainty, the thing a single number hides.
mount: <div class="card"><p class="kicker">Models</p><div class="wx-scroll" tabindex="0"><svg class="mg" viewBox="0 0 994 96" width="994" height="96" role="img" aria-label="ECMWF ensemble (ENS): what it is connected to"><style>.mg text{font:12px var(--sans);fill:var(--ink)}.mg .mg-sub,.mg .mg-verb{font-size:10px;fill:var(--ink-2)}.mg-node rect{fill:var(--surface);stroke:var(--line-2)}.mg-node.me rect{stroke:var(--focus);stroke-width:2}.mg-node.unstated rect{stroke-dasharray:2 3;fill:var(--paper)}a.mg-node:hover rect,a.mg-node:focus rect{stroke:var(--focus);stroke-width:2}.mg-edge{fill:none;stroke:var(--ink-2);stroke-opacity:.55;stroke-width:1}.mg-edge.unv{stroke-dasharray:5 4}</style><path class="mg-edge" d="M232 23C306 23 306 48 380 48"><title>stated on the page: ecmwf.int</title></path><text class="mg-verb" x="240" y="19" text-anchor="start">carries</text><a class="mg-node " href="data-ecmwf-open.html"><rect x="2" y="8" width="230" height="30" rx="4"/><text x="9" y="21">ECMWF open data</text><text class="mg-sub" x="9" y="33">Open data and APIs</text></a><path class="mg-edge" d="M232 63C306 63 306 48 380 48"><title>stated on the page: ecmwf.int</title></path><text class="mg-verb" x="240" y="59" text-anchor="start">runs</text><a class="mg-node " href="body-ecmwf.html"><rect x="2" y="48" width="230" height="30" rx="4"/><text x="9" y="61">ECMWF</text><text class="mg-sub" x="9" y="73">Bodies</text></a><path class="mg-edge" d="M610 48C685 48 685 43 760 43"><title>stated on the page: ecmwf.int</title></path><text class="mg-verb" x="752" y="39" text-anchor="end">is the same model as</text><a class="mg-node " href="model-ecmwf-ifs.html"><rect x="760" y="28" width="230" height="30" rx="4"/><text x="767" y="41">ECMWF IFS</text><text class="mg-sub" x="767" y="53">Models</text></a><g class="mg-node me"><rect x="380" y="33" width="230" height="30" rx="4"/><text x="387" y="46">ECMWF ensemble (ENS)</text><text class="mg-sub" x="387" y="58">Models</text></g></svg></div><p class="wx-legend meta">Left: what points at it. Right: what it points at. Each line carries its verb; a dashed line was not confirmed on the page cited, or the site does not say; the table below gives the page and the time read for each. <span class="prov">From <a href="model-ecmwf-ens.json">model-ecmwf-ens.json</a></span></p></div>
---
# ECMWF ensemble (ENS)

> Kept by incident.meteorology@web-summit.dinis, 11 November 2026, 11:36 UTC

[Where a forecast comes from](../index.md) · Models · id `model-ecmwf-ens` · [as data](model-ecmwf-ens.json)

The same IFS run many times from slightly different starts: the spread between members is the forecast's uncertainty, the thing a single number hides.

**Address:** [https://www.ecmwf.int/en/forecasts/datasets/open-data](https://www.ecmwf.int/en/forecasts/datasets/open-data) (leaves this site)

## What it is connected to, and who says so

| This | Verb | That | The page that says so | Read | Check |
|---|---|---|---|---|---|
| ECMWF ensemble (ENS) | **is the same model as** | [ECMWF IFS](model-ecmwf-ifs.md) | [ecmwf.int](https://www.ecmwf.int/en/forecasts/datasets/open-data): "are published at two resolutions: the existing 0.25 degrees and, from 20 October 2026, a finer 0.1 degrees - both produced from the same IFS model and interpolated to a lat/long grid. The lower resolution data are releas" *The ensemble and the high-resolution forecast are one model, the IFS, run differently.* | 11:28 UTC, 11 Nov | stated on the page |
| ECMWF ensemble (ENS) | **is what ECMWF open data carries** | [ECMWF open data](data-ecmwf-open.md) | [ecmwf.int](https://www.ecmwf.int/en/forecasts/datasets/open-data): "These products are a subset of the full Catalogue of ECMWF Real-time Products and are based on the medium-range ( high-resolution and ensemble ) and seasonal forecast models. IFS data are published at two resolutions: th" | 11:28 UTC, 11 Nov | stated on the page |
| ECMWF ensemble (ENS) | **run by** | [ECMWF](body-ecmwf.md) | [ecmwf.int](https://www.ecmwf.int/en/forecasts/datasets/open-data): "These products are a subset of the full Catalogue of ECMWF Real-time Products and are based on the medium-range ( high-resolution and ensemble ) and seasonal forecast models. IFS data are published at two resolutions: th" | 11:28 UTC, 11 Nov | stated on the page |

## Licence: what we may do with it

No licence row yet covers this node: **unclear** until one does. [The licence table](../licences.md).

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Not a warning service: this page explains where data comes from. For warnings follow [IPMA](https://www.ipma.pt/pt/otempo/prev-sam/) and ANEPC.