Nokia's now a full year into its Windows Phone transition and it appears that Lumia sales have returned to health. After a challenging Q3, the company has just announced its Q4 2012 financial results today, revealing that 4.4 million Lumia devices were sold in its recent quarter. Nokia previously shipped 2.9 million Lumia devices in its previous quarter, making this a return to the kind of sales we witnessed in Q2 (4 million). Up to December 31st, Nokia has shipped 14.3 million Lumias.

Nokia estimated it would sell 4.4 million Lumias in Q4 thanks to some recent guidance, so today's confirmation is hardly surprising. However, Nokia revealed that its North American devices and services volumes were up 40 percent from the same quarter a year ago to 700,000 in total. That's a solid bump from the previous quarter of 300,000 and greater than Nokia's Q2 of 600,000.

Nokia's rolling thunder approach to the US market is still going slowly, but there's signs that its recent product launches are starting to increase sales in that particular market. Nokia is expected to unveil new Windows Phone devices at Mobile World Congress next month too that, if released soon enough, may help it boost Lumia sales for Q1 2013.