Sales of new luxury condominiums appear to have triggered a price spike in Kauai’s housing market last month.

Kauai Board of Realtors data presented in a Hawaii Information Service report Friday show the median price for condos sold on Kauai soared 79 percent in September to $785,000 from $437,500 in the same month last year.

Much of the wild increase looks like it was due to new luxury condos sold in the Poipu resort area.

The number of condo sales in Kauai’s Koloa region that includes Poipu doubled to 20 last month from 10 a year earlier, and the median price there shot up to $860,378 from $530,000. Property records show that among those sales were eight luxury condos at Pili Mai at Poipu sold by the project’s developer for between $800,000 and $900,000.

Those Pili Mai sales drove the median price for the whole island dramatically higher because the median is a point at which half the sales were at a higher price and half at a lower price.

Unlike housing market reports for Oahu from the Hono­lulu Board of Realtors that include only resales of previously owned homes, the Kauai Board of Realtors includes sales of new homes that typically sell for more than older homes.

Overall, there were 39 condos sold on Kauai last month, compared with 36 a year earlier.

In Kauai’s single-family home market, the median sale price rose 6 percent to $681,000 in September from $640,000 a year earlier. There were 56 sales last month compared with 46 a year earlier.

Hawaii Information also released data for Hawaii island home sales from Hawaii Island Realtors.

Single-family homes on the Big Island sold for a median $368,000 last month, up 11 percent from $332,450 a year earlier. That was based on 185 sales in September and 204 a year earlier.

The median price for Hawaii island condos slipped nearly 2 percent to $297,500 on 59 sales last month from $302,000 on 72 sales a year earlier.

Pili Mai sales drove the median price for the whole island dramatically higher because the median is a point at which half the sales were at a higherprice and half at a lower price.