Here’s one sign that the cooling off for housing appreciation has become widespread: The hot San Francisco housing market actually saw home prices drop in July, marking the city’s weakest result since early 2012, according to data released Tuesday morning. Looking at a broader gauge of prices in 20 cities, July saw overall growth of 0.6% in July, slower than the 1% rise in June, according to S&P/Case-Shiller’s 20-city composite index. After seasonal adjustments, home prices among the 20 cities fell 0.5% in July — the biggest drop since October 2011 — compared with a 0.3% decline in June. Slower appreciation could ... (full story)