Home affordability continues to challenge first-time, young and middle-class buyers, with some of the warmer climes generally making for the hottest – and least affordable – housing markets.

But good news if you like the cold – the most affordable markets are near the Great Lakes.

That’s the summary from Jed Kolko, chief economist for Trulia.

“Despite high household incomes, San Francisco is the least affordable metro, with just 15% of homes within reach of the middle class. Affordability has deteriorated over the past year in Austin and Miami,” he writes. “…Affordability has fallen modestly, hurt by rising home prices, but helped by lower mortgage rates.”

Nationally, Kolko says, 59% of homes for sale are within reach of the middle class, compared with 62% last October.

“Nonetheless, the big picture is that prices still look undervalued compared with fundamentals and historically low mortgage rates make buying much cheaper than renting. Still, affordability is a growing problem,” he says. “We measure affordability as the share of homes for sale on Trulia within reach of a middle-class household. Our standard is whether the total monthly payment, including mortgage, insurance, and property taxes, is less than 31% of the metro area’s median household income. We define middle class separately for each metro based on the local median household income. Thus, what we consider affordable varies from market to market.”

For instance, Kolko says, in metro Atlanta, median household income is $55,000. Homes priced under $276,000 are affordable based on the 31% guideline. On November 7, 2014, 71% of the homes for sale in Atlanta were listed for less than $276,000. That means that more than two-thirds of metro Atlanta homes are within reach of the middle class.

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The five most affordable markets are in Ohio, Indiana, and upstate New York. In those markets, more than 80% of homes for sale are within reach of the middle class. The South is relatively affordable too, with Birmingham, Alabama, and Columbia, South Carolina, among the 10 most affordable markets.

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Six of the seven least affordable markets are in California. A middle-class household can afford just 15% of homes for sale in San Francisco and 22% in Los Angeles. In New York, only 25% of homes for sale are within reach. Joining the least affordable list for the first time are Austin and Miami. In Austin, just 40% of homes for sale are within reach of the middle class, down from 50% last fall. Miami has seen a similar drop in affordability. In total, in 20 of the 100 largest metros, middle-class households can afford fewer than 50% of homes.

The full report can be read here