The Farmer’s Almanac makes seasonal forecasts and recently came out with its winter forecast.
The Farmer’s Almanac does not share how it makes its forecasts so it cannot be judged scientifically. There is no proven skill of its forecast accuracy.
It also makes a weather forecast for specific time periods in a given season.
Such detailed forecasts are not trustworthy scientifically.
Seasonal weather forecasting is a modern-day science challenge. The National Weather Service’s Climate Prediction Center also makes seasonal forecasts.
They explain the underlying principles of their forecast and provide validation of their forecasts publicly.
These modern day seasonal forecasts rely on the known relationships between climate and some key forcing mechanisms, such as El Niño.
An El Niño is a periodic warming of the equatorial Pacific Ocean between South America and the Date Line.
This warming is a natural variation of the ocean and is used to predict departures from average conditions rather than to make specific weather forecasts.
For example, a year with a strong El Niño leads to less snowfall than average in Wisconsin.
These seasonal forecasts also take into account the climatic impacts of other global oscillations.
These relations are uncovered by research conducted by atmospheric scientists, and while we understand these relationships, we cannot yet predict the occurrence of these key forcing mechanisms, such as the development of an El Niño.
Currently, there are no strong global patterns developing that allow for a confident prediction of our winter weather conditions.
There are equal chances our wintertime weather conditions will result in temperatures above, below or at average.