Summer travel was surprisingly robust in the United States, despite a slew of factors that threatened to keep visitors at home.

According to the U.S. Travel Association’s Travel Trends Index, released Tuesday, travel volume in the U.S. was up 4.4 percent in August compared to a year earlier.

“Although travel has outperformed the economic recovery overall, our grip on prolonged growth has felt tenuous at times because of the dollar’s impressive run and a rogue’s gallery of other concerning factors,” Roger Dow, president and CEO of the U.S. Travel Association, said in a statement. “Between TSA’s early summer issues, Brexit, Zika, and a tumultuous U.S. election cycle, it’s been a year of news stories that don’t particularly create the yearning to travel, particularly among internationals. Here is evidence that travelers around the world have been able to look past the headlines to see the reality: the U.S. is open for business.”

Both domestic business travel and domestic leisure travel grew at a faster pace in August than they had in previous months, while international inbound travel increased at a slower pace.

But the report warned that the growth in domestic leisure travel is likely to slow with the end of the peak summer travel period. Domestic business travel — which has been on a roller coaster ride all year — is forecast to stay “stagnant.”

Overall, U.S. domestic travel is expected to grow just 1.4 percent through the beginning of next year.

While searches for lodging show that interest in the U.S. has grown among foreign travelers, the expectation is still for international inbound travel to grow slowly or decline into early 2017.

“Travel is still expanding—but given the recent weakness in international inbound visitations, domestic leisure travel will be the key to growth going forward,” David Huether, the association’s senior vice president for research, said in the report. “While we hope that more international visitors will act on their increased interest in the U.S. as a destination, it will likely be on domestic leisure travelers to carry the travel economy through the end of 2016.”

Photo Credit: This photo shows a view from the South Rim of the Grand Canyon National Park in Arizona. Travel volume in the U.S. increased in August as visitors took advantage of low fuel prices and the summer break. Rick Bowmer / Associated Press