The best time to visit United States

What a year in United States looks like

The United States does not have one season, it has a dozen running at once: the July that makes Arizona unwalkable at midday is the only month when every mountain road in Montana is open. The Gulf and the eastern seaboard live under the Atlantic hurricane season, which normally runs from early June to late November and peaks around late August into early October, while the Pacific coast barely knows that weather exists. Summer is when the national parks are fully open and fullest of people; winter is when the Rockies and New England sell snow instead. Autumn and spring are the two windows when most of the country is pleasant at the same time, which is exactly why they are the hardest weeks to book.

The year, in windows

• January to March — This is full ski season in Colorado, Utah and Vermont, with the snowpack usually deepest around midwinter. At the same time south Florida, Arizona and Hawaii fill up with Americans escaping their own winter, so those two groups of places run busy while the rest of the country is quiet. Northeastern cities can take a snowstorm that cancels flights in a chain reaction across several hubs. Build a spare day into any tight itinerary in these weeks.
• April to May — Spring moves north a week at a time. The cherry blossom in Washington, D.C. usually lands in late March or early April but shifts every year, so check that season's own bloom announcement rather than a date you remember. The southwestern deserts are at their most comfortable now, which makes Zion, Joshua Tree and Big Bend far better in these weeks than in July. The central plains, meanwhile, enter their severe thunderstorm season, and high mountain passes in the Rockies and Sierra may still be closed by snow.
• June to August — Summer is when every mountain road is finally open, so Yellowstone, Glacier and the high Yosemite country are all reachable at once. It is also when school is out: car parks fill before nine, and lodging inside the popular parks is normally booked many months ahead. The South and Southwest turn hot and heavy enough that walking is a morning and evening activity only. The Atlantic hurricane season is counted from the start of June, though most years it stays quiet until the tail of this window.
• September to October — After the Labor Day weekend at the start of September the parks empty out almost overnight while the weather is still good, and the leaves begin turning from the north downward, usually peaking in New England and Michigan somewhere in the first half of October. This is also the exact peak of the hurricane season, so anyone flying into Florida, the Gulf coast or the Carolinas should hold a changeable ticket. In the West, wildfire smoke can drift across several states and flatten the views for days at a time. On balance it is still the best-value window of the year.
• November to December — These weeks belong to the cities rather than the landscape: New York, Chicago and San Francisco move into end-of-year mode, and museums and theatres become the main event. The hurricane season closes at the end of November, which settles Florida down again. The Thanksgiving week in late November and the stretch from Christmas to New Year are the two busiest airport periods of the American year, and fares behave accordingly. Ski areas start opening from late November onward depending on how the snow has come in that year.

The weeks to aim for

For good weather across the widest spread of the country at once, aim at mid-September to mid-October: the parks are still fully open, the school-holiday crush has gone, and the colour is coming in up north. For a city-led trip, May and early June give long daylight, warmth you can walk in, and fares that have not yet hit the summer peak. If snow is the point, mid-January to early March is normally when the base is deepest and the lifts are all turning. What rarely works is trying to combine the western parks and the Gulf coast in one month, because their good seasons barely overlap.

The weeks to avoid

Late August into early October is the busiest part of the hurricane season, and anyone building a Gulf coast, Florida or Carolinas trip into those weeks is accepting that a week of plans might have to move. That is not a prediction of a storm, only a reason to keep a second option. Mid-July in Phoenix, Las Vegas and Death Valley is hot enough that almost everything outdoors has to shift to first light. Thanksgiving week and the days around New Year are when airports and interstates are at their worst; going then is perfectly possible, but the trade is time and flexibility rather than money.

What the season does to a data plan

Distance is what drives data use here. A cross-state drive means turn-by-turn navigation running for hours a day, which burns far more than a week of walking around one city. In the western national parks the signal often disappears for an entire valley, so download offline maps and your booking confirmations before you leave the last town that has service. Ski season adds a different problem: a phone held in cold air on a chairlift loses charge unusually fast, so keep it in an inside pocket and carry a battery pack. During hurricane season the airline app and the local emergency notices are the things you must be able to reach at any hour, and that is a poor argument for relying on hotel Wi-Fi, which goes down with the power.