How Accurate Is Farmers’ Almanac?

Every fall, the winter forecast from the Farmers’ Almanac makes its rounds online. It promises a “frosty,” “frigid,” or “snowy” season ahead, pointing to a secret formula locked in a vault. The National Weather Service releases its own outlook around the same time, using satellite data and atmospheric models. One prediction is ancient and mystical; the other is modern and scientific.

But when the final snowpack melts and the average temperature is tallied, which forecast actually held up better? The almanac itself prints an eye-catching number — 80% accuracy — that fuels its reputation every year. Independent researchers who have actually tested the predictions against recorded weather data found a much more modest result, and understanding the gap is worth your time if you’re planning anything around a long-range forecast.

The Almanac’s Famous 80% Claim

The Farmers’ Almanac (published in Lewiston, Maine) and the Old Farmer’s Almanac (published in Dublin, New Hampshire) are two separate brands. Both have been around for well over a century, and both claim their long-range forecasts land around 80% correct.

That number comes straight from the publisher. The Old Farmer’s Almanac says its accuracy is “calibrated” year after year. The method is a proprietary formula involving sunspot activity, planetary positions, and lunar cycles. The exact details are kept secret, which makes the claim impossible for outside scientists to replicate or verify independently.

Eighty percent is a bold claim. For context, a modern short-range forecast from NOAA (two to three days out) hits about 90% accuracy. Seasonal outlooks from the National Weather Service are much more conservative in their success rates. So an 80% seasonal forecast from a secret formula would be remarkable if it held up.

Why The 80% Stat Stays Popular

Even if the scientific basis is shaky, a lot of people check the almanac every year. A few common psychological patterns explain why the reputation persists despite the mixed evidence.

• Nostalgia and ritual: Checking the almanac is a generational habit for many families. It feels like a piece of inherited wisdom, not a data feed.
• Confirmation bias: People remember the predictions that came true — the big blizzard in February — and mentally brush past the warm snap in January that the almanac missed entirely.
• Vague regional language: Long-range predictions use broad terms like “colder than normal” or “brisk temperatures.” Over a three-month season, almost every region has some period that fits the description.
• Headline appeal: A dramatic almanac headline (“Polar Coaster Winter Ahead”) drives clicks and conversation, even if the actual forecast is modest or vague.

These factors give the almanac more cultural staying power than its raw statistical track record might support on its own.

What Independent Studies Actually Found

When researchers checked the almanac against ground truth, the numbers shrank considerably. A 2010 analysis from the University of Illinois compared the published predictions to what weather stations actually recorded. The results landed around 52% — essentially identical to random chance.

The almanac’s official website maintains its predictions average upward of 80% accuracy, but the university’s statistical check found no evidence that the secret formula outperformed a simple coin flip over the long term. Other weather-news outlets have run similar independent audits and arrived at similar conclusions.

The 52% figure is a far cry from the advertised 80%. It suggests the moon-phase and sunspot approach is no more predictive for seasonal weather than guessing based on historical averages.

Factors That Skew The Accuracy Score

Assessing the almanac’s accuracy fairly is harder than looking at one national average. A few factors make the number slippery depending on how you define a “correct” forecast.

1. Regional vs. local outcomes: A zone forecast might correctly predict cold for the Northeast, but your specific city in that zone might have a mild month. The almanac counts it as a win; you experience it as a miss.
2. Vague prediction definitions: “Colder than normal” sets a low bar. If the temperature average is 1 degree below the 30-year normal, the forecast is technically correct, even if the winter felt mostly typical.
3. Lack of transparent methodology: Because the formula is proprietary, no researcher can audit the inputs. A black-box forecast makes it difficult to separate genuine predictive skill from statistically expected hits.

These nuances mean a single accuracy number doesn’t tell you how useful the almanac is for your specific commute, your heating bill, or your holiday travel plans.

Almanac vs. Modern Meteorology

The gap between the two approaches is stark. The gap between the almanac’s claims and the independent check was quantified by the audit of almanac forecasts, which remains the most widely cited external analysis. Modern meteorology relies on physics-based models, real-time satellite feeds, and ocean-buoy data. The almanac relies on a centuries-old recipe that hasn’t been published for peer review.

The National Weather Service winter outlook uses the same tools that predict hurricane tracks and tornado outbreaks. It has known limitations — seasonal forecasting is hard even with supercomputers — but the methodology is transparent and continuously refined.

For a sense of general winter trends, the almanac is a conversation starter. For a decision that depends on actual weather — a roof replacement, a road trip, an outdoor event — the 7-day forecast from a local meteorologist is the more reliable tool.

The Bottom Line

The Farmers’ Almanac and the Old Farmer’s Almanac are pieces of living folk history with devoted followings, and their long-range predictions are fun to read. The best available independent evidence shows their seasonal forecasts are correct about half the time — essentially no better than chance — despite the publishers’ claims of 80% accuracy. Modern NOAA forecasts, especially in the 1-to-10-day window, dramatically outperform that baseline for specific locations.

If you’re making a major outdoor plan next winter, the 7-day forecast from your local National Weather Service office is based on real-time physics, not a vaulted secret formula.