# Climate Birthday

Which day of the year now has the weather your birthday used to have?

Which day of the year now has the weather your birthday used to have? Per-city daily climatologies from ERA5 reanalysis, pre-industrial vs today, inverted to find your climate birthday - and the days whose weather no longer exists.

Interactive tool: pick a day and month and the globe shows, for cities around the world, the day whose present-day mean temperature matches what your birthday had before industrialisation.

Data: ERA5 via the Open-Meteo archive API (daily mean 2 m air temperature). Baseline 1951–1980 shifted by −0.3 °C to approximate pre-industrial; current period 2006–2025.

Part of [Jacob Davies](https://jacob-davies.com/).