Metro Phoenix’s median home price climbed more than 5 percent in May and is more than 10 percent higher than a year ago.

Demand from homebuyers, particularly for relatively affordable houses, continues to grow as the number of houses for sale shrinks.

The Valley’s median home price reached $223,000 in May, up from $212,000 in April. In May 2014, the area’s median price was $200,000.

Home sales ticked up 1 percent during May, while houses listed for sale fell 7 percent.

“Tight supply” describes the housing market now, said Mike Orr, director of the Center for Real Estate Theory and Practice at Arizona State University’s W. P. Carey School. “This is causing problems for buyers who are experiencing multiple bids in the range below $200,000.”

Bidding wars have broken out over affordable Phoenix-area houses during the past few months as more first-time and boomerang buyers have opted to buy.

Orr thinks June was another strong month for sales, though he is still analyzing the data.

He is forecasting home sales will slow a bit during the hot months of July and August and then pick back up in the fall with home prices continuing their climb then.

“If the current supply shortage persists through the third quarter, we should expect upward price pressure to resume at the end of September,” he said.