What was the weather like on the day you were born?

It's not a hypothetical question anymore.

Thanks to a new tool released this month by the Copernicus ECMWF Climate Change Service, you can find out — hour by hour, anywhere on Earth, going back to January 1940.

It's called : <<< Weather Replay >>>

And it is genuinely extraordinary.

The app is a time machine for the atmosphere.

Select any date from the past 85 years, click any point on the globe, and within seconds you can watch the weather of that moment unfold: temperature, wind, pressure, precipitation, gusts, jet streams.

The full 48-hour evolution.

All powered by the ERA5 reanalysis dataset and ECMWF's meteorological archive.

This new app can be your time machine to revisit past weather.

Weather Replay from @copernicusecmwf enables anyone to revisit the weather anywhere on the globe, hour by hour, from January 1940 up to a few days before present.

Try it out 👉 https://t.co/ieoaI4fVs0 pic.twitter.com/pH0bKpi7Zj

— World Meteorological Organization (@WMO) May 24, 2026

 A quiet, beautiful demonstration of why investment in the global observation and reanalysis enterprise pays off across science, policy, and public understanding.

 

Why this matters beyond the "wow" factor:

• Reanalysis is one of the most useful products in modern climate science.
• It blends decades of observations with state-of-the-art atmospheric models to reconstruct a physically consistent record of every hour of weather, everywhere.
• Until tools like Weather Replay, that record lived mostly inside research institutions.
• Now it is open, intuitive, and accessible to anyone — students, journalists, communicators, citizens, decision-makers.

Con Weather Replay, la nueva app de @CopernicusECMWF puedes reconstruir las condiciones meteorológicas de cualquier lugar del mundo hora a hora desde 1940 hasta hoy.https://t.co/sGFQ5AfM8W pic.twitter.com/knp9UybGpw

— IGEO (CSIC-UCM) (@IGeociencias) May 21, 2026

It was 70 years ago, on the afternoon of February 15th 1941 that a windstorm burst on Portugal with unprecedented ferocity. 

The storm caused significant damage and disruption, making a direct hit on Lisbon while damaging winds affected the whole of Portugal.