• by Erik Sass  @eriksass1, July 6, 2010

The strong momentum enjoyed by national spot radio in the first half of the year is continuing into the third quarter, according to Katz Radio, which is reporting big year-over-year increases in ad sales for the summer months.

On a monthly basis, Katz is projecting increases of 13% in July, 16% in August, and 28% in September, for an overall projected increase of 18% for the quarter.

Katz has seen major increases in a number of categories, including retail, up 21.4% in the second quarter and 23.2% in the third; automobiles, up 29.5% and 39%, respectively; consumer products, up 32.6% and 56.9%; professional services, up 29.6% and 28.4%; and telecoms, up 38.2% and 11.3%.

Major third-quarter advertisers include big names like Verizon, Safeway, Geico, AT&T, Home Depot, Wal-Mart, Allstate, Comcast, Fox, Honda and Dodge.

In terms of geographic distribution, Katz says 85 of the 100 top media markets have enjoyed revenue increases for the year-to-date in 2010, with the top 10 markets up 13.3% in the third quarter and sales up 20.9% across all markets. Geographic leaders include Boston, up a whopping 72%; Miami, up 54%; and Denver, up 56%, according to Katz.

While the national spot sales picture is cheery, the rest of the radio industry isn't doing nearly so well, especially in the critical area of local sales.

In the first quarter, while national spots sales jumped 19%, local sales increased just 2%, according to the Radio Advertising Bureau. The anemic local sales figures suggest radio will have a hard time winning back the billions in local ad revenues lost over the past few years. From 2006-2009, total radio ad sales plunged from $21.66 billion to $16 billion, a 26.2% drop, per the RAB.