Can they still not predict rain even one week in advance?
I am going to pause and say I don't know anything about SMHI. Therefore I can't comment on their competency. But I am sure they don't appreciate being called incompetent. If you are so passionate about rain, have you considered looking at weather prediction, and trying to beat them?
It is well known that the limit for predictability of weather is 2 weeks. Past that, climatology is just as accurate as modern forecasts in the grand scheme of things. Individual events may have more or less predictability. Precipitation is very hard to forecast, for various reasons including the lack of quality water vapor observations, the complexity of microphysics, and the interaction with other atmospheric physics.
It really depends on the mechanism for rainfall. Different mechanisms have different amounts of predictability. For example, a 5-day forecast of a hurricane is off by an average of 200 miles (321 km). Thunderstorms, especially individual cells, are hard to predict without probability. Extratropical cyclones are a bit easier predicted.
Farmers almanacs are notoriously inaccurate. Moreover, their &quot;predictions&quot; are fuzzy. You'll find better accuracy with actual forecasts.