The dog days of summer dampened Manhattan’s luxury market for the second week in a row, as buyers and sellers skipped town for vacation, according to the Olshan Report on Monday.

Only 13 homes priced at $4 million or more went into contract in the week ending Sunday, according to the report Olshan Realty publishes weekly. It’s the second week in a row new contracts have fallen below 20 since January—marking a cyclical lull in activity as many of the city’s well-heeled home owners head to the Hamptons or abroad.

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Not a single home on the Upper East Side went into contract for the first week since New Year’s 2016. Donna Olshan, president of Olshan Realty, and author of the report, called it the “typical summer swoon.”

Those homes that did find buyers last week added up to only $98.6 million, the first time weekly transactions fell below the $100 million mark in months. In total, nine condos, four co-ops and no townhouses transacted.

The most expensive home to find a buyer last week was a west side condo overlooking the Hudson River asking $15.5 million. The four-bedroom apartment is part of the Waterline Square complex, which is comprised of three architectural glass towers. This particular sale was in a building designed by starchitect Richard Meier. The project says the buildings will offer niche amenities like a golf simulator, squash court, dog playroom and rock climbing wall.

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The second most expensive contract was also in a building designed by a Pritzker prize winner, Rafael Vinoly. The three-bedroom condo on Fifth Avenue went into contract asking $11.8 million.