I just bought a copy of The Old Farmer's Almanac and wonder how the authors are able to make weather predictions for an entire year. Are they accurate? (I would imagine they must be since it's been around since 1792.)

I've checked several over the years and found them pretty inaccurate. But they were using folk wisdom, which is not as reliable as science. Even science is lousy when it comes to forecasts of over about a week. After that, they have to rely on very general sorts of predictions e.g. this is (or is not) an El Nino year, or a sunspot year, or whatever.

Folk wisdom makes generalizations but they are not accurately recorded and compared as carefully as scientific data is.

Some of the short term folk wisdom is pretty good:

Ring around the moon, rain by noon.
Ring around the sun, rain before night is done.

A halo around the sun or moon is caused by ice crystals in cirrus clouds. That usually means wet weather is 12 to 18 hours away.


When the dew is on the grass, rain will never come to pass.

Heavy dew on a summer night forms when skies are clear and the temperature has dropped. Plan on fair weather.

http://wcpo.com/weather/weather_myths.html

One of the most apt sayings I heard was "Red sky at night, the barn's on fire!"

LOL, fourbrick!

Check out The Old Farmer's Almanac "formula",

Predicting the Weather

If memory serves me correctly, it was the Old Farmer's Almanac, that sometime during the 1800's, predicted snow in July. The guy writing the forecast was doing it as a gag. When July came, just so happen there was a volcano erupted somewhere. It put out so much, the atmosphere was affected in such a way, it ended up snowing. As a result, The Old Farmer's Almanac gained credibility that still stands to this day.