Apple’s iOS mobile operating system added five points to its market share lead over Google’s Android in the mobile ad market, accounting for 62% of mobile ad impressions as compared to Android’s 38%, according to Velti’s September “State of Mobile Advertising” report. Just under half the iOS total originated in the U.S., followed by Japan with 14% and the U.K. at 8% of mobile ad impressions.

“In July and August, Android held prevalent market share in a year that was previously dominated by iOS—but September marks an end to this trend,” noted Velti CMO Krishna Subramanian. “We are seeing a pattern that leads us to believe the shift back to iOS domination is a result of the iOS 6 release and iPhone 5 launch. In fact, this is similar to the change we saw directly after the iPhone 4S release, when iOS volume also spiked by five percent.”

Though the latest iOS version 6 was taken up quickly “among a large amount of iOS users,” 11% decided against upgrading and have stuck with iOS 4, Velti found in its latest research. Velti researchers found that users of the new iPhone 5 spent 27%  iPhone 5 time on social networking applications, 22% on games and 13% each on entertainment and utility apps.

Apple’s presence across the mobile market ecosystem isn’t as commanding in other countries and regions as it is in the U.S., Velti noted. Samsung clearly leads in its home market of South Korea, where it is the #1 device manufacturer as well as the leader in mobile ad impressions by a sizable margin, according to Velti’s findings. Apple’s best showing in South Korea is its iPhone 3 and iPhone 4, which were the third and fourth most widely used smartphones, respectively.

Other findings from the new report include:

  • Samsung’s Galaxy S III: Samsung’s Galaxy S III entered the top five devices on the exchange this month, capturing 1 percent of all impressions.
  • AT&T leads U.S. carriers with over half of all iPhone impressions. Verizon comes in second with just under a third of impression volume.
  • Weather Surge: Weather is once again the leader on the eCPM Index, after being beaten by Education apps in August.