These are the cheapest dates to book a flight

Flights are up to 90 per cent cheaper if you know when to go

Flying off season can reap financial rewards (Getty Images/iStockphoto)

Travellers can save nearly £500 on return flights to New York, £386 on flights to Dubai and £676 on flights to Bali, just by picking the right day to fly.

Flights can be up to 90 per cent cheaper when booked for the least expensive days of departure, according to research from travel search engine Kayak.

It compared prices of return flights to the 10 most popular international destinations for Brits based on searches made between 1 January 2017 and 31 July 2018, with travel dates between 1 August 2017 and 31 July 2018.

Flights to New York cost £141 on average on the cheapest day, 10 January, compared to the most expensive day, 29 July, when they were £491 more expensive.

The data shows that booking flights to Ibiza departing 13 April cost passengers just £11 on average – a whopping £274 cheaper than on the most expensive day, 25 May.

On flights to Sydney, the difference in cost can be as great as £900. On 9 May, the average flight cost £435; on 19 December last year, the average price rocketed to £1,313.

Holidaymakers can also bag a bargain hotel room if they travel out of season.

The average price for a hotel room in Prague dropped to just £22 on the cheapest night, 17 January. However, just a couple of weeks earlier on 29 December, prices were at their most expensive, rising to £142 on average.

Outside Europe, hotels at some destinations can cost 10 times as much on the most expensive day of the year compared to the cheapest. On 7 April, the average cost for a night in a Marrakech hotel was £23; on the most expensive day, 28 July, prices rose to an average of £298 per night.

“It’s no secret that travelling out of season can be cheaper, but the data shows that in some cases, changes of just a few days can mean huge differences,” says John-Lee Saez, managing director for Kayak Europe. “In some cases, the most expensive and cheapest days to fly to certain destinations were just a couple of weeks apart.

“So for savvy travellers who are flexible with dates, and more concerned about seeing the destination than having perfect weather there, the savings can be massive. It really can help you see the world for less.”