Secrets of the Almanac’s Forecasts

Plus, September’s full Moon, shorter days, making the most of blackberries, and more! [From The Old Farmer's Almanac]( [Almanac]( Thank you Jacklyn Pennington in Corbin, KY, for [this week's cover image!]( When the annual edition of The Old Farmer’s Almanac is released each year, it includes weather forecasts made up to 18 months in advance. Have you ever wondered how our prognosticators do it? The core of the Almanac’s forecasting methodology dates back to our origins in 1792. Founder Robert B. Thomas created the secret formula that we still use today. This series of notes and equations—which is kept in a black box under the desk of our editor—is unique in that it incorporates the science of sunspots, which are magnetic storms on the surface of the Sun. Over the years, the use of solar science has been enhanced to include the analysis of prevailing weather patterns and the atmosphere. This means that phenomena like El Niño and La Niña are also considered in the Almanac’s forecasts. So, how accurate are the Almanac’s predictions? Traditionally, Almanac editors claim 80% accuracy. This number isn’t just made up. For each new Almanac, the actual observations of temperature and precipitation during the previous year for many thousands of locales are compared with our forecasts for each area. Across the U.S., for the winter and spring of 2019–2020, the Almanac was 72.2% correct for temperature and 88.9% accurate for precipitation, for an average of 80.6% accuracy. Pretty close to our traditional number and not bad for forecasts finalized months in advance! You can find the full methodology behind our weather forecasting model, how we evaluate the accuracy of each year’s forecasts, and, of course, our predictions for the coming year in [The 2021 Old Farmer’s Almanac, which is available now](! Our [fall forecast]( is now available online, too—giving you plenty of time to prepare for the [autumnal equinox]( on September 22. The Old Farmer’s Almanac may be best known for its annual weather forecasts, but its knowledge of astronomy comes in a close second. This week brings [September’s full Moon](, along with still-clear summer skies in many areas to make for good viewing. By the way, it isn’t your imagination: The days are getting shorter! We make it easy to stay on top of [sunrise](, [sunset](, [moonrise](, and [moonset]( times with our handy calculators. Finally, late summer means blackberries! Savor a taste of summer any time of the year with [blackberry jam](! As sure as the Sun will rise and set each day, The Old Farmer’s Almanac is here for you, now and always. Your Friends from The Old Farmer’s Almanac “Climate is what we expect, weather is what we get.” –Mark Twain (1835–1910), American writer and humorist FOLLOW US ON INSTAGRAM [@THEOLDFARMERSALMANAC]( [Full Corn Moon]( Don’t forget to look up! The Full Corn Moon rises just after sunset on Tuesday, September 1, reaching its peak illumination at 1:23 A.M. Eastern Time on Wednesday, September 2. Learn how the Full Corn Moon got its name here: [Almanac.com/content/full-moon-september](.[Almanac.com/news/home-health/natural-living/cucumbers-health-benefits]( WHAT WE'RE DOING THIS WEEK [Reading The 2021 Old Farmer’s Almanac]( [READING THE 2021 OLD FARMER'S ALMANAC]( [Planning for Fall]( [PLANNING FOR FALL]( [Marveling at the Full Corn Moon]( [MARVELING AT THE FULL CORN MOON]( [Making Blackberry Jam]( [MAKING BLACKBERRY JAM]( [Facebook]( [Instagram]( [YouTube]( [Pinterest]( [Twitter]( [Visit Almanac.com]( [Shop Our Store]( New to this newsletter? It’s free! [Sign up here](. You received this email because you signed for updates from The Old Farmer's Almanac. If you do not wish to receive our regular e-mail newsletter in the future, please [click here to manage preferences](. *Please do not reply to this e-mail* © 2020 Yankee Publishing Inc. An Employee-Owned Company 1121 Main Street | P.O. Box 520 | Dublin, NH 03444 [Contact Us]( [View web version](