Forecast Ireland is the Irish member of the Forecast network, the companion to Forecast Britain. It shows the operational models of the two national weather services whose forecasts cover the island — the Met Office's and Met Éireann's — on one atlas, in one set of colours, so that they can be read against each other.

The Met Office

• UKV — the Met Office's 2 km convection-permitting configuration of the Unified Model over Britain, Ireland and the near continent. The 3-hourly long runs go to 54 hours.
• Global — the 10 km global run, hourly to 54 hours and 3-hourly to seven days. It carries the town forecasts past the UKV's horizon.
• Global Wave — WAVEWATCH III on a 25 km grid, forced by the Global run.

These come from the Met Office's open data on AWS and are rendered by Forecast Britain; Forecast Ireland serves the same frames, framed on Ireland. The town forecasts read the values back out of those frames — each frame's palette is a reversible encoding of its field — which is good to about half a degree and a km/h or two.

Met Éireann

HARMONIE is Met Éireann's own model: HARMONIE-AROME, run on the DINI domain of the UWC-West partnership (Denmark, Iceland, the Netherlands and Ireland) as the DINI-EPS ensemble. Met Éireann publishes its Ireland cut openly at opendata2.met.ie/nwp — a new cycle every hour, 2 km, 60 hours ahead, as GRIB2. This site reads the control member of the 00, 06, 12 and 18 UTC cycles and renders it itself, through exactly the palettes the UKV uses, so a UKV frame and a HARMONIE frame at the same valid time are a like-for-like comparison.

Three things are derived here rather than published: sea-level pressure (the feed carries surface pressure and surface height; it is reduced with the standard hypsometric formula, which agrees with the UKV's to well under a hectopascal over the island); total cloud (combined from the low, medium and high layers — the feed's "total cloud at 2 m" is fog); and hourly rain (the difference of successive run totals). Met Éireann's warnings are fetched every ten minutes from its open-data feed.

The atlas plate

The front-page map is drawn in Irish Transverse Mercator — the projection of the island's national grid, shared by Tailte Éireann and OSNI — on its central meridian of 8°W, which runs down the middle of the island. The relief is made here from the Copernicus GLO-90 elevation model and NOAA's ETOPO 2022 bathymetry by the network's atlas maker: multidirectional hillshade and texture shading, keyed to the island's own heights so that the Reeks, the Mournes and the Wicklow granite read as mountains without painting the midland bogs brown. Provinces, counties, loughs and the border are Natural Earth's. Irish place names follow logainm.ie.

What it is not

This is an independent visualisation of model output, not an official forecast. For warnings and for any decision that matters, use Met Éireann and, in Northern Ireland, the Met Office.

Credits and licences

• Contains Met Office data licensed under the Open Government Licence v3.0.
• Copyright Met Éireann. Source met.ie. This data is published under a Creative Commons Attribution 4.0 International (CC BY 4.0) licence. Met Éireann does not accept any liability whatsoever for any error or omission in the data, their availability, or for any loss or damage arising from their use. Modified by forecastireland.com: regridded to Web Mercator, colour-mapped, sampled at places; sea-level pressure, total cloud and hourly rain derived.
• Copernicus GLO-90 DEM: © DLR e.V. 2010–2014 and © Airbus Defence and Space GmbH 2014–2018, provided under COPERNICUS by the European Union and ESA; all rights reserved. ETOPO 2022: NOAA NCEI. Natural Earth: public domain.
• Basemap tiles on the maps, and the explorer's coastline and border drawn from them: © OpenStreetMap contributors, via Protomaps.