I'm not a farmer, but I have relied on the farmers almanac before when planning vacations months in advance. It's been surprisingly accurate at determining whether a given week would have rain, snow, or sun. I have no idea how they did it but I would love to see their weather prediction system open sourced if they're going to be shutting down.
Better yet, use the NWS climate outlook, based on actual science: https://www.cpc.ncep.noaa.gov/
They do detailed scoring of their predictions and it's based on rigorous physical modeling (navier stokes) so they know that it's better than chance. FA hasn't held up well to such scrutiny.
For Europe, use ECMWF, they provide great data: https://www.ecmwf.int/en/forecasts
Does something like this exist for weather prediction worldwide?
Sadly it would never work for the British Isles, that much I can guarantee you. Our weather resists all forms of prediction found to be reliable elsewhere, and I doubt AI enhancements over the next few years will make much of a dent in the problem.
I’ve tried all manner of weather services and none of them really do a really good job of any level of forecasting. They do however excel at supplying me with information I can get just by looking out the window.
Statistical averages and confirmation bias.