Measured, not imagined.

Each poster is generated from ERA5, the fifth-generation global atmospheric reanalysis produced by the European Centre for Medium-Range Weather Forecasts (ECMWF) on behalf of the Copernicus Climate Change Service. ERA5 covers the full global atmosphere at hourly intervals from 1940 to five days ago, on a grid of approximately 31 km.

Reanalysis is not a forecast. It is a reconstruction of the past atmosphere using every available observation — from weather stations, radiosondes, ships, aircraft, and satellites — combined with a state-of-the-art weather model. The result is a consistent, physically coherent picture of the atmosphere at every point in time and space.

When you specify a place and a date, the server retrieves the ERA5 wind field for that location and hour. The visualisation is drawn directly from those values. Nothing is estimated, smoothed for aesthetics, or generated from a forecast. The atmosphere on your day is exactly what ERA5 recorded.

The Weather Poster is a tool for turning a date and a place into a fine-art print. It was built by people who work with atmospheric data professionally and wanted a way to make that data visible in a form that was both scientifically accurate and worth hanging on a wall.

The visualisation draws particle trails that trace the real wind vectors. The colour palette is chosen to emphasise the atmospheric structure rather than decorate it. The result looks different for every date and place because the atmosphere is different for every date and place.

The download is a full set of print-ready files at multiple aspect ratios. The largest outputs are sharp at 24×36 in (61×91 cm). Printing and framing are left to you.