WASHINGTON—Home sales fell more than expected in February as cold weather blanketed many parts of the country, and a rebound could be muted by rising mortgage rates as well as higher house prices amid tight supply. The National Association of Realtors said on Monday that existing home sales dropped 6.6 percent to a seasonally adjusted annual rate of 6.22 million units last month. Economists polled by Reuters had forecast sales would drop 3.0 percent to a rate of 6.50 million units in February. Home resales, which account for the bulk of home sales, increased 9.1 percent on a year-on-year basis. Last month, sales declined in the Northeast, South and the Midwest, but rose in the West. Bitterly cold weather, including severe winter storms in Texas and other parts of the densely populated South region, disrupted economic activity last month, depressing retail sales, production at factories and homebuilding. Warmer temperatures, an …