Forecast Hungary is the Hungarian member of the Forecast network. It puts the national weather service's own models beside the two European ones — HungaroMet's AROME and WRF, DWD's ICON-EU and ECMWF's HRES — over the whole country and the Carpathian Basin around it, at the same instant, on one atlas.

The models

• AROME (HungaroMet) — the convection-permitting model, 2.5 km (0.025°) over 14.3–24.3°E, 44.9–49.5°N, runs at 00, 06, 12 and 18 UTC, hourly to +48 h. The flagship of the maps.
• WRF (HungaroMet) — the second limited-area model, about 1.6–2.4 km (0.0212° × 0.0143°) over 13.9–24.5°E, 44.3–49.9°N, the same four runs, hourly to +36 h, with simulated composite radar reflectivity.
• ICON-EU (Deutscher Wetterdienst) — the European nest of DWD's ICON, 6.5 km, eight runs a day, hourly to +48 h and three-hourly to +120 h, with 850 hPa, 700 hPa, 500 hPa and the jet. Rendered by Forecast Germany.
• ECMWF HRES — the European Centre's high-resolution global forecast from its open data at 0.1°, four runs a day, to six days (+144 h as Forecast Euro publishes it). Rendered by Forecast Euro.

Where the frames come from

HungaroMet publishes AROME and WRF on its Open Data Portal as one NetCDF file per variable and lead time, on regular latitude–longitude grids, from about 1¾ to 3¼ hours after each run starts. Those files are fetched as they appear, decoded (temperatures from kelvin, pressure from pascals, WRF's cloud from okta, the run-total rain differenced into hourly steps), and drawn into the same kind of frame the other two models use. ICON-EU and ECMWF are not downloaded here at all: Forecast Germany and Forecast Euro render them once, and this site reads the same frames through its own server.

How a number is made

Every frame is a palettised PNG in Web Mercator whose palette is a reversible encoding of the field, published with a catalog that says how to undo it. The map shows the colours; the pointer readout, the compare panel, the city values and the point view read the colour back to a value, to the precision of the frame's own palette. Wind direction comes from each model's u/v sidecar raster, and the isobars are contoured upstream from the full-precision pressure field, not from the picture. The four palettes differ, so a colour on one model is not a colour on another — compare the values, which this site prints in one set of units (°C, km/h, mm by default; °F, mph and inches on the toggle).

Time

Every valid time is shown on Budapest's clock — CET (UTC+1), or CEST (UTC+2) from the last Sunday of March to the last Sunday of October. Runs keep their UTC names. Switching model holds the valid time, not the forecast hour.

The front page, and EOV

The plate on the front page is drawn in EOV — the Egységes Országos Vetület, Uniform National Projection (EPSG:23700), on which every Hungarian map since 1975 has been drawn. It is an oblique Mercator: the GRS67 ellipsoid onto a Gauss sphere, then a cylinder tangent along a great circle running east–west through Gellérthegy, with a scale factor of 0.99993 so the error stays within ±0.07 % from Szentgotthárd to Záhony. Its grid coordinates are Y east and X north, offset so that every point in the country has Y > X. The relief under it is made here from the Copernicus GLO-90 elevation model. The maps are in Web Mercator instead, because that is the projection the model frames are rendered in and the one the shared basemap tiles are cut to; at 47°N over a country this size the difference is a few per cent of scale, not of shape.

Licences and credits

• HungaroMet: Database: Meteorological Database, HungaroMet Nonprofit Zrt. — graphically reproduced data. Free use under the ODP general terms of use; the maps here are reworked from the published files, and that is what "graphically reproduced" says.
• DWD: Datenbasis: Deutscher Wetterdienst (ICON-EU), CC BY 4.0.
• ECMWF: contains modified Copernicus/ECMWF open data, © European Centre for Medium-Range Weather Forecasts, CC BY 4.0.
• Basemap and geography: © OpenStreetMap contributors (ODbL) via Protomaps; borders, counties and lakes Natural Earth; lakes and rivers on the plate OpenStreetMap; place names GeoNames (CC BY 4.0); relief 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).

Not a warning service

This is not an official forecast. For warnings use HungaroMet's met.hu.