Orange County’s housing market ended 2016 with its overall median selling price at an all-time high of $665,000 as local builders had their best sales month in 12 years.

CoreLogic reported Tuesday that for the third consecutive month, Orange County’s median was at an all-time high as it surged from $660,000 in November and $655,000 in October. In a year, the local median price is up 5 percent.

Prices are on the upswing – 56 consecutive months of year-over-year increases – as the local job market remains strong, the supply of existing homes for sale remains tight, and successful house hunters are switching to pricier new homes. Rising mortgage rates, and fears they will go higher, motivated buyers at year’s end.

Here are 10 things you need to know about December’s upswing:

1. Sales high: Countywide, 3,250 homes sold in December. Yes, that overall pace is down 9 sales from a year earlier, but December 2015 was the fastest-selling last month of the year since 2005. For the year, 37,881 Orange County homes sold, the best year since 2006.

2. Mixed results: These were not uniform trends, geographically speaking. At the neighborhood level, medians were up in 53 of 83 Orange County ZIP codes compared to December 2015. Sales rose in 36 of 83 ZIPs.

3. Builders are hot: They sold 671 homes, up 22 percent in a year. That’s the biggest one-month sales count for developers since December 2004. For the year, 4,690 new homes were sold, up 29 percent vs. 2015 and the highest since 2006. December’s median was $835,000 – that is off 2.5 percent in a year.

4. Builders a growing force: Developers took in 20.6 percent of all home sales countywide in December, a share up from 16.8 percent a year earlier and the largest share for new homes in 9 years. For the year, 12.4 percent of all sales were new homes, up from 9.9 percent a year ago and also the highest share since 2007.

5. Price matters. Sales in the 27 least expensive ZIP codes – median sales price at $556,000 and below – fell 5.6 percent compared to a year ago. In the 27 priciest ZIPs – median sales price beginning at $749,000 – sales jumped 13.8 percent compared to a year ago. Limited supply of low-end homes to buy is largely to blame.

6. Slow for homes. Buyers snapped up 1,800 existing single-family homes countywide, down 2 percent in a year. The median price was $700,000 – that is up 4.5 percent in a year. For the year, sales were up just 0.6 percent vs. 2015 as limited supply and builders’ competition hurt.

7. Condos even slower. Sales of existing condos totaled 779 homes, down 11 percent in a year. The median price was $435,000 – that is up 3.6 percent in a year. For the year, sales were up only 0.4 percent as a significant shortage of listings to choose from frustrated condo shoppers.

8. Luxury is slow, too. In the 11 Orange County ZIPs with median selling prices above $1 million, sales totaled 250 homes, down 1.6 percent compared to a year ago. December’s most expensive ZIP code was Newport Coast 92657 at $3.74 million. Next was Newport Beach 92661 at $3.6 million.

9. In line with region. Just like Orange County, sales in the Southern California counties dipped (but it was a somewhat noteworthy 3 percent drop) while the median price rose (a solid 7 percent) to $470,000. The SoCal median is at its highest since August 2007 but below its all-time high of $505,000 reached earlier that year.

10. Slow start for ‘17 resales? Two other benchmarks suggest homebuying challenges for resales of Orange County residences. ReportsOnHousing says the year started with 4,071 homes list for sale, 53 percent below the average Jan. 1 supply since 2005. And the California Association of Realtors’ pending sales index, tracking deals signed to buy a house, was down 11 percent in December vs. a year earlier.

Contact the writer: jlansner@scng.com