To calculate month to month typical prices, KAYAK takes all price ranges for monthly over the last 12 months for flights from London Heathrow Airport to Austin, gets rid of the best 0.1% to account for outliers, after which you can can take the median of all values for monthly. https://ilovebookmarking.com/story18517363/not-known-details-about-flights-to-atlanta-from-london