Southern California home sales hit the brakes in June, falling to the lowest reading for the month in four years. Sales of both new and existing houses and condominiums dropped 11.8 percent year over year, as prices shot up to a record high, according to CoreLogic. The report covers Los Angeles, Riverside, San Diego, Ventura, San Bernardino and Orange counties.

Sales fell 1.1 percent compared with May, but the average change from May to June, going back to 1988, is a 6 percent gain.

The weakness was especially apparent in sales of newly built homes, which were 47 percent below the June average. Part of that is that builders are putting up fewer homes, so there is simply less to sell.

“A portion of last month’s year-over-year sales decline reflects one less business day for deals to be recorded compared with June 2017,” noted Andrew LePage, a CoreLogic analyst. “But affordability and inventory constraints are likely the main culprits in last month’s sales slowdown, which applied to all six of the region’s counties and across most of the major price categories.”

The median price paid for all Southern California homes sold in June was a record $536,250, according to CoreLogic, a 7.3 percent increase compared with June 2017. While part of that is due to a mix shift, since there are fewer lower-priced homes for sale, it is becoming increasingly clear that fewer buyers are able to play in the higher price ranges.

“Sales below $500,000 dropped 21 percent on a year-over-year basis, while deals of $500,000 or more fell about 3 percent, marking the first annual decline for that price category in nearly two years,” said LePage. “Home sales of $1 million or more last month rose just a tad – less than 1 percent – from a year earlier following annual gains of between 5 percent and 21 percent over the prior year.”

LePage points to the rise in mortgage rates over the past six months, increasing significantly a borrower’s monthly payment. Rates haven’t moved much in the past month, but are suddenly going higher again this week, pointing to even further weakness in affordability.

In the past, California, one of the largest housing markets in the nation, has been a predictor for the rest of the country. Home prices have been rising everywhere, amid a critical housing shortage. Prices usually lag sales by several months, and sales are beginning to crumble, even as more inventory comes on the market. The supply of homes for sale increased annually in June for the first time in three years, according to the National Association of Realtors, but sales fell for the third straight month.