California existing home sales rose to their highest level in nearly four years in June, rising 10% from May and 2.2% from a year earlier to a seaonally adjusted annual rate of 450,960 units, the California Association of Realtors reported late Monday.

The month-to-month increase was the first double-digit monthly gain since January 2011 when sales of existing homes rose 11.3% from December 2014.

Rising demand combined with tight supply kept upward pressure on prices in June. The median price of an existing, single-family detached California home increased 5.5% in June to $519,440 from $492,320 in June 2015. June's median price was 0.1% lower than the revised $519,750 recorded in May 2016.

"The annual gain in the median home price is being driven by more sales at the mid-segment housing market, which comprise at least half of the overall demand," said C.A.R. Vice President and Chief Economist Leslie Appleton-Young. "Price growth appears to be cooling somewhat in San Francisco, where the 3.2% increase was less than the statewide gain of 5.5%."

Other data in the C.A.R. report included:

  • C.A.R.'s Unsold Inventory Index, which indicates the number of months needed to sell the supply of homes on the market at the current sales rate, dipped slightly to 3.2 months in June from 3.4 months in May. The index stood at 3.2 months in June 2015. At the state level, there were 2.6% fewer homes available for sale in June compared with a year earlier. The long-run average home supply is 6.1 months, indicating inventory levels are running at roughly 60% of normal.
  • The median number of days it took to sell a single-family home dipped slightly in June to 27.1 days, compared with 27.3 days in May and 28 days in June 2015.
  • According to C.A.R.'s sales-to-list price ratio, tight inventories also appear to be driving final sales prices closer to listing prices, with sales prices slightly decreasing to 99.6% of listing prices statewide in June from 99.7% in May.
  • The average price per square foot for an existing, single-family home statewide was $247 in June 2016, down from $248 in May but up from $237 in June 2015.
  • San Francisco County had the highest price per square foot in June at $837/sq. ft., followed by San Mateo ($793/sq. ft.), and Marin ($633/sq. ft.). Counties with the lowest price per square foot in June include Siskiyou ($122/sq. ft.), Tulare ($126/sq. ft.), and Kern and Kings ($131/sq. ft.).
  • Mortgage rates are expected to remain low in the foreseeable future due to global economic uncertainty. Mortgage rates declined in June, with the 30-year, fixed-mortgage interest rate averaging 3.57%, compared with 3.60% in May and 3.98% in June 2015, according to Freddie Mac. Adjustable-rate mortgage interest rates slipped in June to an average of 2.78%, a decline from 2.81% in May and 2.99% in June 2015.