That’s actually an end goal! I’m thinking of setting up a system to crowdsource this: if people opt in, the tool could cache the weather data it pulls and share it to help build a distributed historical dataset.
There are meteorological services with open data access: https://www.ncei.noaa.gov/cdo-web/, https://english.knmidata.nl/open-dat, https://climatedataportal.metoffice.gov.uk/
Mapping that would be quite a bit of work, I imagine.
Yeah, mapping it would definitely be a project. I looked into using open data from those sources, but ran into issues where the values didn’t match what MSN reports (which is what the Windows weather widget uses). Even small differences in temperature or how conditions are worded ("partly sunny" vs. "mostly sunny") can throw off the match. I’m planning to try using open data for historical screenshots eventually, but I expect it’ll reduce accuracy greatly.