To calculate every day regular price ranges, KAYAK normally takes all costs for each day just before departure over the past 12 months for flights from Fort Lauderdale to Atlanta, eliminates the highest 0.1% to account for outliers, then can take the standard of all the values for every month. https://whitemagictravels.co.uk/blog/how-does-the-travel-agents-milton-keynes-be-your-best-choice/