Buy the 2015 Old Farmer's Almanac!
Reporting
curdled sky is the same ascurdled sky is the same as buttermilk sky - that was one of the ways my grandfather watched for rain. Curdled/Buttermilk sky is usually altocumulus clouds -usually on a warm and humid summer morning & usually followed by thunderstorms. We dont have mackerels in this area so I guess that mackerel sky never became a catch phrase down in my neck of the woods.

2015 Garden Calendar2015 Weather Watcher's Calendar2015 Recipes Calendar2015 Engagement Calendar 2015 Everyday Calendar2015 Country CalendarNew Year Cross StitchLobster Rope Doormats