We need some new old sayings...
And here's your chance to say 'em. Rules of Thumb is a new website that solicits, lists and allows comments on folk wisdom.
Most of them are unadulterated hogwash. An example:
A curdly sky never leaves the ground dry.
Check out the entries on farming.
I think this is all part of the anti-technology backlash that fuels agrarian agriculture and seeks to re-establish experiential wisdom over technological discovery.
Good luck with that.