A lot of the oomph that had been propelling Oahu’s housing market into record territory this year has dissipated for a second straight month with near-flat median sale prices.

Sales statistics set for release Tuesday by the Hono­­lulu Board of Realtors show that the median sale price for previously owned single-family houses on the island edged up by 0.5 percent to $678,500 in September from $675,000 in the same month a year earlier.

It was the smallest gain for any month this year, and followed a 2.3 percent decline in August.

Still, the median price for the first nine months of the year is up 4.6 percent at $669,500 due to gains earlier in the year that ranged from 3 percent to 13 percent and included a single-month record set in June at $700,000.

In Oahu’s condominium market, the median sale price in September edged down by 0.3 percent to $347,000 from $348,000 a year earlier. That followed no change in August after gains between 2 percent and 13 percent earlier in the year that produced a single-month record set in June at $360,000.

For the first nine months of this year, the median condo price is up 5.4 percent to $350,000 from $332,000 a year earlier.

Local economist Paul Brewbaker said in a recent email that he doesn’t see any break in an underlying upward pricing trend, though he noted that home price gains this year appear subdued given that the average annual growth rate since the mid-1980s — including periods of booming prices and declines — has been around 5 percent.

"It’s unusual for the cycle at this stage of the expansion to have such moderated rates of price increase, but on the other hand that means that the housing cycle can extend itself for longer," he said.

The recent cooling off in the market has been somewhat reflected in a recently revised report from the University of Hawaii Economic Research Organization, which lowered its median price projection for single-family houses this year.

UHERO’s latest report, which was released in August, pro­jects a 6.1 percent gain for the single-family house median price. That is down from a 9.8 percent gain forecast in a March report.

For the median condo price, UHERO slightly elevated its projection for the year to 6.8 percent in its August report from 6.2 percent in the March report.

In terms of sales volume, Oahu home purchases continued what has been a choppy year of ups and downs.

The number of single-family houses sold in September was up 5 percent to 318 compared with 303 in the same month last year. Year-to-date sales are up 1.6 percent after rising in five months and falling in four months.

Condo sales volume dipped 1.4 percent in September to 415 from 421 a year earlier.

Year-to-date sales are down 0.4 percent after rising in five months and falling in four months.