Dallas Texas Arts District
Seventy-six percent of HotelTonight's bookings in Dallas are for the same night, which have it tied for second as the most spontaneous U.S. city.
| Credit: joe daniel price/Getty Images

Southerners are more likely to make last-minute travel plans.

According to data from HotelTonight, all of the top 10 U.S. cities where people are most likely to book hotel rooms for that night are located in the southern part of the country.

Those in Atlanta came in first place for the most spontaneity in their hotel booking plans. HotelTonight reports that 77 percent of their bookings in Atlanta were for the same night. Hotel room seekers in Denver and Dallas tied for second place, with 76 percent. The list was rounded out by Houston, Los Angeles, Baltimore, Phoenix, Fort Lauderdale, Orange County (California), and Austin.

But even in the most spontaneous cities, the day you choose to book can affect how much you save.

Atlanta Georgia Piedmont Park
A whopping 77 percent of HotelTonight's bookings in Atlanta are for that night.
| Credit: SeanPavonePhoto/Getty Images

“If you’re looking to book a last minute spring staycation, Sundays tend to be the best day to book a hotel room across the board,” said HotelTonight spokesperson Emma Leggat. “But if you look at the rest of the week, some days are better than others in different cities.”

Denver Colorado Union Station
Tied for second with Dallas, 76 percent of bookings in Denver were for the same day.
| Credit: Blaine Harrington III/Getty Images

Surprisingly, those looking for a last-minute hotel room in big metropolises like New York City, London, Paris, or San Francisco could find great deals on Friday night, Shank said. (Must be all those business travelers.) Friday night rooms can drop as low as $110 in Paris, and $128 in London.

It differs elsewhere around the country. The best days to book a last-minute room are Monday in Los Angeles (when rooms are $173), Tuesday in Miami ($112), and Thursday in Chicago ($122).