Every year since George Washington was president, The Old Farmer’s Almanac has predicted the weather. And every year in recent times, we publish an analysis of our forecast from the previous year.

How Accurate Is The Old Farmer’s Almanac Weather Forecast?

We believe that nothing in the universe happens haphazardly, that there is a cause-and-effect pattern to all phenomena. However, although neither we nor any other forecasters have as yet gained sufficient insight into the mysteries of the universe to predict the weather with total accuracy, our results are almost always very close to our traditional claim of 80% accuracy.

The 2019-2020 Prediction

As a reminder, The 2020 Old Farmer’s Almanac predicted that the 2019–2020 winter season would bring below-normal temperatures from the Heartland westward to the Pacific and in the Desert Southwest, Pacific Southwest, and Hawaii, but above-normal temperatures throughtout the rest of the country. Precipitation was predicted to be below normal in Florida and the Gulf Coast area, Texas, Oklahoma, the Upper Midwest, the western Desert Southwest, central California, and western Hawaii and above normal in all other regions. 

We predicted below-normal snowfall in much of the country and above-normal snowfall from the southern Appalachians northward through western Pennsylvania, most of Ohio and the Heartland, from northern Michigan westward to the Puget Sound, Alaska, and the Intermountain region. 

How Accurate Were We Last Year?

Our overall accuracy rate came out to 80.5%, which is just above our traditional average rate of 80%. This rate is calculated by comparing our predicted changes in temperature and precipitation to the actual observed changes.

The only regions in which our temperature forecasts were incorrect were the Atlantic Corridor, Florida, Intermountain, Pacific Southwest, and Hawaii. In precipitation, we were correct in all regions with the exception of the Ohio Valley and Upper Midwest.

Most of the places in the northern tier of states had above-normal snowfall. We also forecast “Snowy” in Alaska, and many parts of the state did have above-normal snowfall. Nearly every place else that normally has winter snowfall was below normal. We did indeed forecast below-normal snowfall in most of these areas, but we forecast too much snow in most spots from the Appalachians westward to the Intermountain region.

Traditionally, The Old Farmer’s Almanac still has about an 80% accuracy track record. These numbers are determined by looking at monthly averages—since these are long-range monthly predictions—as opposed to judging each day’s forecast.

See our full recap with more details in The 2021 Old Farmer’s Almanac.

How We Make Our Forecast

We derive our weather forecasts from a secret formula that was devised by the founder of this Almanac, Robert B. Thomas, in 1792. Thomas believed that weather on Earth was influenced by sunspots, which are magnetic storms on the surface of the Sun.

Some people don’t believe that the minute amount of energy the sun bears could have any influence on the atmosphere and therefore the climate and the weather, but we are among those that do.

In addition to solar science (the study of sunspots), we rely on climatology (the study of weather patterns) and meteorology (the study of the atmosphere).

Of course, our exact formula is a secret. But rest assured, the meteorological technology and methods are continually updated. While principals upon which the forecasts are made are essentially the same, we use the latest state-of-the-art satellite data, all the latest technology and equipment.

Read more about how we predict the weather.

Get Weather Predictions for 2021

How cold and snowy will this winter be? For specifics on snowfall and temperatures in your region, pick up The 2021 Old Farmer’s Almanac—now available for pre-order!

And for our very best value package—including our most popular Almanac products—join The Old Farmer’s Almanac Best Value Club Charter Membership!