Trends in the weather since 1940

Work in progress, enjoy the public preview while we work out the bugs.

While much of the climate focus is rightly on present day challenges and future climate projections, this project puts the spotlight on the recent past.

Our planet has already warmed by 1.2 degrees over pre-industrial levels.

Of course global averages don't tell the whole story. In our daily lives, we don't feel the global average - we think about the local extremes! Questions like:

How many days of frost did we get in March last winter, compared to the past?
How many days of extreme heat have we experienced this decade?

Please enjoy this data-driven exploration. The historical weather record is provided by the ERA5, the fifth-generation global weather reanalysis from the Copernicus Climate Change Service. Data was made analysis-ready and cloud-optimized for temporal access by Earthmover, who graciously hosts the data on AWS.

My hope is that, by describing the historical weather record objectively, we can have more productive climate conversations on strategies to mitigate and adapt to climate changes.

Data Sources

Icechunk ERA5 was accessed from https://registry.opendata.aws/earthmover-era5.

This dataset was generated using Copernicus Climate Change Service information 2026. Copernicus Climate Change Service, Climate Data Store, (2023): ERA5 hourly data on single levels from 1940 to present. Copernicus Climate Change Service (C3S) Climate Data Store (CDS). DOI: https://doi.org/10.24381/cds.adbb2d47 (Accessed in 2026). Copernicus Climate Change Service, Climate Data Store, (2023): ERA5 hourly data on pressure levels from 1940 to present. Copernicus Climate Change Service (C3S) Climate Data Store (CDS). DOI: https://doi.org/10.24381/cds.bd0915c6 (Accessed in 2026). Historical backfill from the NSF NCAR Curated ERA5 archive: European Centre for Medium-Range Weather Forecasts. 2019, updated monthly. ERA5 Reanalysis (0.25 Degree Latitude-Longitude Grid). Research Data Archive at the National Center for Atmospheric Research, Computational and Information Systems Laboratory. https://doi.org/10.5065/BH6N-5N20.