If you want to get the cheapest fares for flights leaving at the start of the school summer holiday in 2020, you should book flights tomorrow, on 4 January.
That's the conclusion of Which? Travel researchers, who crunched fares on millions of flights listed on Skyscanner in 2017 and 2018 to identify when flights were cheapest for popular holiday periods.
Flights for the school break need to be booked the furthest in advance out of all the holiday dates we checked. Summer holiday fares were cheapest six months and one to two weeks ahead of departure - when they were 7% cheaper, on average, than at other times of the year.
The price of flights can go up even during the 10 minutes when you're actually booking them. This is what airlines call 'dynamic pricing', or hiking prices when demand for a certain destination or flight is higher.
While the Skyscanner data allows us to predict the best time to book for flights in 2020, dynamic pricing means it isn't an exact science. However, when we looked at the data from 2017 and 2018, we found that the best time to book for different holidays was roughly the same in each year. This means that while the best prices for the summer should be in the next day or two, fares are likely to remain below average for week or so after 4 January.
Which? Travel can also help you decide where to go on your next summer break. We asked thousands of holidaymakers to rate the food, beaches, and peace and quiet in the - read about table-topping Puerto Calero in Lanzarote and why you should avoid Arrecife.