Good luck finding cheap airfare from the United States in the summer, but there are still a few deals to be had if you know where to look.

The travel and tourism industries are inherently seasonal. Broadly speaking, travel is more expensive in summer and less expensive in winter. But choosing the cheapest time to fly to a specific locale is more nuanced, according to an analysis of airfare data by Hopper, a flight search engine.

For many US origins, it’s cheapest to fly to European destinations in winter, but Dallas-based flyers find the cheapest fares to London and Amsterdam in fall. Spring is the cheapest time for New Yorkers to make it out to Los Angeles or San Francisco, but a traveler from Chicago would save money by waiting until winter to travel to the west coast.

One thing is nearly constant, however: Summer is rarely the cheapest time to fly anywhere from anywhere. According to Hopper’s analysis only six routes of the 770 between the worlds most popular airports are cheapest in summer. The five routes with the largest winter to summer price swing all rise more than 50%.

As you can explore in the above graphic, Hopper analyzed airfares with origins at each of the 15 most popular airports in the US. It looked at point-to-point published fares, which were not necessarily direct flights, to the other 14 US airports as well as the 50 most popular airports globally.

Some airport pairs are not possible, such as a New York’s Kennedy to New York’s LaGuardia. Others in airports in the same city showed different seasonal low points, likely the result of only small amounts of variation season-to-season or a low point near the boundary of a season.