Fall is almost here, making it prime time to plan a trip to see beautiful foliage across the country.

However, as any avid leaf peeper will tell you, fall can be fickle. So before booking a ticket to your favorite sweater-weather destination, you should do your homework on when the leaves actually shift from their summer greens to fall reds, oranges, and yellows.

Thankfully, the work is done for you with SmokyMountains.com's fall foliage map, which uses an in-depth algorithm to predict the changing of the leaves every year.

"In 2013, potential visitors to the Smoky Mountain region began asking us questions about when the leaves would be most brilliant. From these questions, we built the first version of the fall leaf map and have consistently improved it each year," David Angotti, the map's creator and brand founder, shared in a statement provided to Travel + Leisure. "What started as a fun side-project quickly became the most respected nationwide fall leaf map and one of the best fall resources in the country. Now, tens of millions of people use our map each year to plan vacations, weddings, and photography trips."

So, how exactly does it work? The map uses a complex algorithm to analyze millions of data points to forecast county-by-county fall foliage. The data includes everything from NOAA historical temperatures, NOAA historical precipitation, NOAA forecast temperatures, historical leaf peak trends, and even user-generated reports.

"In addition to the past factors, we are introducing the capability for end-users to provide real-time leaf reports that will impact both updates and future models," Angotti said. "However, similar to any meteorological forecast that is dependent on weather variables, the leaf predictions are not 100% accurate. That being said, after publishing our predictive fall foliage map for nearly a decade, we are confident in our data sources, process, and algorithm."

The website, however, goes far beyond telling you when the leaves will change. It also goes deep into the science of how.

For example, on SmokyMountains.com, visitors can learn about the compounds that make leaves change to either orange, red, or yellow and further explains why leaves fall in the first place.

"The beauty of nature is sometimes found in the profound 'intelligence' it exudes. Perennials, which includes trees, must protect themselves in order to get through the harsh, freezing temperatures of winter. If trees did not shed their leaves, their soft vegetation would certainly freeze during winter time, damaging and, no doubt, killing the tree," the website explained.