It’s hardly a secret that airfares fluctuate a lot. Knowing the best time to purchase a flight has turned into something like Russian roulette for travelers – if you don’t “win” a low fare, you can lose big and be left with a sense that there has to be a better way. That’s where we come in.

Every year, CheapAir.com analyzes hundreds of millions of domestic and international airfares – and you can read about the results of our domestic When to Buy Flights study, where we show you the best time to buy a domestic flight. But we also track international tickets, and this year we took a deeper dive into the international data to provide our customers with the most comprehensive insights we’ve ever shared.

In our study, we reviewed a total of 917,000,000 airfares, including fares covering more than 1,000,000 international trips over the last year. These airfares covered more than 3,000 international markets. For each trip, we studied all the possible days you could buy that airline ticket – to uncover when international flights have the lowest fares.

We identified the best day to buy a ticket in the different regions around the world, and we identified the “prime booking window” for each region as well. The prime booking window is the range of days in which you are likely to see the lowest fares – the window where it’s generally not too early to get a good deal, but also not too late. If price is most important, you should plan to purchase your flights within this range. Of course, the prime booking window is a generalization, and you should be aware of events like large festivals, international sports events, and major holidays. At a very busy time for the destination – Oktoberfest in Munich, the Edinburgh Festival in Scotland, and Holi in India are just three examples that come to mind – you’ll want to buy in the early part of the prime booking window, or in some cases even earlier. Otherwise, use the prime booking window as a good estimate of when it will make the best sense to buy.

We also looked at whether traveling in certain seasons will impact when you should buy your flights, and which travel months had the highest and lowest airline ticket prices for each region. Finally, we analyzed the days of the week to determine whether there was a price advantage to buying, or flying, on any particular day.

Here is a breakdown of the average number of days before departure that yields the lowest airline ticket price for U.S. travelers heading to international regions:

We’ll now review each region in more detail, and address how to approach buying a ticket to each destination, using a range of criteria as explained above:

Canada

The Canadian market is very similar to the U.S. market – it’s best to buy your airline ticket to Canada 66 days in advance, on average. Flights to Canada are about 3% cheaper than they were last year on average, which is a modest savings but hey—we’ll take a modest savings over a modest increase any day! No big surprises that Canada’s warm summers see the most expensive airline tickets, with July being the most expensive month to visit, but still – the difference between July and October (the least expensive month) is relatively modest—about $64.

Prime Booking Window: 3 weeks to about 5 months before departure

Best time to buy: About 66 days from your travel date

The average airfare: $427

Cheapest month to travel: October

Most expensive month to travel: July

Least expensive days of week to fly: Tuesday and Wednesday

Mexico/Central America

Mexico and Central America were quite similar to domestic U.S. flights (this has not always been the case in the past) – you can generally wait about 70 days out for the best fares to Mexico or Central American destinations. The airfares to our neighbors to the south are also trending slightly cheaper overall versus last year, translating to an average 3% savings on each ticket. December is the most expensive month, so get your Christmas beach vacation booked stat!

Prime Booking Window: 2 weeks to almost 6 months before departure

Best time to buy: About 70 days from your travel date

The average airfare: $489

Cheapest month to travel: September

Most expensive month to travel: December

Least expensive days of week to fly: Tuesday and Wednesday

Caribbean

On average, the cheapest flights to the Caribbean are found when you buy that tropical airline ticket a whopping 207 days in advance – nearly 7 months before you go. The prime booking window is enormous as well – which frankly, is good news to travelers. You don’t really have to scrutinize the calendar as closely when the fluctuations in price remain fairly small over the course of most of the time before your trip. Having said that, the fares do still jump up in that last month before you plan to go. And you should also pay close attention to booking holiday flights early if you’re spending Christmas or Hanukkah in Jamaica. December is the priciest month to travel.

Prime Booking Window: 1 month to almost 11 months before departure

Best time to buy: About 207 days from your travel date

The average airfare: $545

Cheapest month to travel: January

Most expensive month to travel: December

Least expensive days of week to fly: Tuesday and Wednesday

South America

Airfares to South America will set you back the fewest dollars on average at 110 days out—closing in on three months before you go. Tickets are a bit more expensive, and are trending more expensive than last year. Travelers can expect to spend an average of 8% more – about $65 more than they would have paid in 2017. One reason for this might be that destinations like Colombia and Argentina are pretty hot right now – the ole’ supply and demand driving up prices. It’s almost $250 cheaper to visit South America in February (the cheapest month to go) than in December. That’s a savings of nearly $1,000 for a family of four!

Prime Booking Window: 5 weeks to almost 11 months before departure

Best time to buy: About 110 days from your travel date

The average airfare: $845

Cheapest month to travel: February

Most expensive month to travel: December

Least expensive days of week to fly: Tuesday and Wednesday

South Pacific

A vacation to Australia, New Zealand, Tahiti or other South Pacific spots in theory should be planned pretty far in advance, as the cheapest time to buy clocks in at 197 days before takeoff. But here again, the prime booking window is very wide, which means that the airfares are not very volatile for a good chunk of time. Because flights are already so expensive, if you have a trip in December (summer down under), you can expect to pay more than $550 more on average than if you travel in the cheapest month of May. That’s a gargantuan argument for visiting in late spring, wouldn’t you say? Airfares to South Pacific destinations are also a modest 3% cheaper this year – so visitors do have that going for them!

Prime Booking Window: 54 days to just over 8 months

Best time to buy: About 197 days from your travel date

The average airfare: $1,708

Cheapest month to travel: May

Most expensive month to travel: December

Least expensive days of week to fly: Tuesday and Wednesday

Asia

Airline tickets to Asia are cheapest right around 4 months (120 days) in advance. The prime booking window is also quite wide for Asia, so you can relax a bit and not worry that prices are going to have a huge spike while you’re watching and waiting. November is the cheapest month to travel with the popular North American travel month of June being the most expensive. Travel in the least expensive month can save you $420 on average. Insider Tip: Asia is a huge region, so we urge our readers to do some research on their own – using our Best Time to Buy Flights Widget. You’ll want to fine-tune these results for your particular itinerary.

Prime Booking Window: A little over a month to 7 months

Best time to buy: About 120 days from your travel date

The average airfare: $1,113

Cheapest month to travel: November

Most expensive month to travel: June

Least expensive days of week to fly: Tuesday and Wednesday

Europe

The cheapest airline tickets to Europe are, on average, found 160 days before departure, and prices have dropped close to 10% since last year (great news for North American travelers, as Europe is always a pricey but coveted vacay – every little bit helps)! One way that the data was a little different for flights to Europe – the best days to travel include Monday—more options! It’ll probably come as no surprise that July is the most expensive time to go across the pond; if you can handle the weather March is the best value hands down, with an average savings of $371 dollars per ticket. We know that people usually try to tackle Europe in the summer, so for more guidance on the best days to fly to Europe this summer (with a handy color-coded calendar for reference), see our Europe Summer Flights page.

Prime Booking Window: About 1.5 months to a little more than 8 months

Best time to buy: 160 days from your travel date

The average airfare: $1,151

Cheapest month to travel: March

Most expensive month to travel: July

Least expensive days of week to fly: Monday, Tuesday and Wednesday

Africa/Middle East

If you’re traveling to a country in Africa or the Middle East, you’ve got some wiggle room in the “when to buy” department. The prime booking widow is pretty wide, so there aren’t huge variations in price for much of the time leading up to a flight. The absolute best best airfares to Africa and the Middle East are found 199 days in advance, close to 7 months, on average.

Prime Booking Window: 96 to 287 days before departure

Best time to buy: About 199 days from your travel date

The average airfare: $1,238

Cheapest month to travel: February

Most expensive month to travel: July

Least expensive days of week to fly: Tuesday and Wednesday

There you have it. The insider’s scoop on 2018 international travel. In case you want to do further research, here are a few more airfare tools for you to check out:

When to Buy Domestic Flights Study

Guide to Summer Flights

Please feel free to comment with your individual questions below – we always take the time to address each question and/or comment from our readers and we know that planning an international trip can be a complex undertaking. We love helping people plan trips. We’re also pleased to offer monthly payments for flights, which can sometimes help make budgeting less stressful for international trips. Happy travels!