Oahu’s housing market shook off five months of sluggishness with double-digit sales increases in August, though weakness persisted for median prices.

A report released Wednesday by the Honolulu Board of Realtors showed that purchases of previously owned single-family homes jumped 21 percent last month to 279 from 231 a year earlier. Condominium sales rose 15 percent to 338 from 294.

The gains were the first since February for any month compared with the same month last year, and have given some industry officials optimism that what appeared to be a slump might be over.

"The double-digit increases in sales of both single-family homes and condominiums are positive signs for the Hawaii market," Joyce Nakamura, president of the Ho­no­lulu Board of Realtors, said in a statement. "We’re cautiously optimistic that this reflects a glimmer of consumer confidence, especially among the lower-priced single-family homes, which is where we often see condo buyers entering the single-family market."

Of course it will remain to be seen whether sales gains are sustained. Over the first eight months of the year, single-family home sales are down 3.5 percent while condo sales are down 0.8 percent.

On the price side, single-family homes and condos remain in negative territory, where they have been almost every month this year.

The median price for single-family homes sold in August was down 13 percent to $557,500 from $641,277 a year ago. Year to date, the median is down 4.2 percent at $570,000.

Condos sold for a median $300,000 in August, down 1 percent from $303,000 a year earlier. Year to date, the median is down 1.6 percent at $300,000.

Some economists last year or early this year had been predicting that Oahu’s housing market this year would build on a recovery in sales and median prices that was established last year and followed several years of dramatically lower demand and a year or two of modest price declines.

Last month, the gain in demand was largely driven by activity in Oahu’s biggest housing submarkets.

On the Ewa Plain, there were 40 single-family home sales last month, a 67 percent increase over 24 sales a year earlier. The median price there was $445,250, up from $427,500.

In Oahu’s second-biggest submarket, Waipahu, sales more than doubled to 28 from 13 while the median price slipped to $500,000 from $505,000.

For condos, sales were also up in the two biggest submarkets. In Waikiki, sales rose 19 percent to 63 last month from 53 a year earlier. The median price also was up to $291,444 from $237,750. And in Makiki-Moiliili, sales rose 25 percent to 45 from 36 while the median price slipped to $285,000 from $330,000.

Though buyer demand increased last month, there are still fewer properties on the market than last year.

There were 1,552 single-family homes listed for sale last month on Oahu, down from 1,779 a year earlier. Condo inventory totaled 1,947 in August compared with 2,260 a year earlier.

Single-family homes sold last month after spending an average 31 days on the market before a binding sales contract was signed, down from 35 days a year ago. Condos spent an average 41 days on the market, up from 33 days.