San Francisco’s housing market is cooling down. This week’s S&P/Case-Shiller home price index showed that San Francisco’s market may become more “normal” in the coming months, though affordability would remain a problem, according to Ralph McLaughlin, Trulia’s chief economist.For now, the pace of home-price growth is slowing. The S&P/Case-Shiller 20-city composite fell by 0.1% month-on-month in June, the third straight decline, while it rose 5.13% year-on-year. June marked the fifth consecutive month in which the year-on-year increase was equal to or smaller than the prior month’s print. One caveat here, however, is that the S&P/Case-Shiller index is more reflective of price changes for premium homes, McLaughlin said.