In every annual Old Farmer’s Almanac edition, we show you how accurate our forecast was for the previous winter. However, because the publication cycle requires that we finalize the weather for the print edition in the spring, before summer weather occurs, we have not been able to include analyses of our summer season forecasts in the Almanac. So, how did we do?
For those interested, here is a summary of how accurate our 2017–2018 winter forecast was.
How Accurate Was Our 2018 Summer Forecast?
You may find it surprising that in the 22 years that I have been the lead meteorologist with final responsibility for these forecasts, our accuracy rate for the summer forecasts has been nearly the same as that for the winter forecasts (80%), even though our forecast year starts with winter and summer is half a year later.
Usually, the further in advance forecasts are made, the lower their accuracy rate. But the methodology that we follow, basing our forecasts on solar cycles, seems to enable us to forecast the summer weather with about the same level of accuracy as achieved by our shorter-term winter forecasts.
In The 2019 Old Farmer’s Almanac, we noted that “Our overall accuracy rate in forecasting the direction of temperature change from normal in the 2017–18 winter … was 83%,” while our “forecast for the change in precipitation from last winter was correct in 72% of the regions.”
When we look at how we did in the forecast for the 2018 summer season (June through August), we find that our accuracy rate was even higher.
In both our temperature and precipitation forecasts, we correctly forecast the correct direction of departure from normal for at least one of the cities in 16 of the 18 U.S. regions and in 6 of the 7 Canadian regions. This is an accuracy rate of 88.9% for the United States, 85.7% for Canada, and 88.0% overall.
We did miss in our temperature forecasts for U.S. regions 16 and 18 (Pacific Southwest and Hawaii) and Canadian region 5 (Southern British Columbia), and we were wrong in our precipitation forecasts for U.S. regions 15 and 18 (Pacific Northwest and Hawaii) and Canadian region 6 (Yukon). Everywhere else, we were correct in our forecasts.
I apologize to our many, many friends in Hawaii, the only region where we were wrong in both our temperature and precipitation forecast departures from normal—we expect better results from our forecasts there for next summer!
The methodology that we use to make our forecasts is unique and has been developed over decades of use, adjustment, and refinement. While we will likely never be perfect in our forecasts, we do strive to learn from our mistakes and to always provide you, our readers, with the best forecasts possible as of the date that we make them.
To find out our long-range predictions for the coming year (November 2018 to October 2019), get your copy of The 2019 Old Farmer’s Almanac—now available!