May was quite a warm month for many people; investors in Pandora (NYSE:P) would probably agree. The Internet radio purveyor saw notable upticks in several of its key metrics for the month. Total listener hours were 1.35 billion all told, a 22% gain from May 2012's figure of 1.10 billion. A higher increase was recorded in the number of active listeners; this advanced a robust 33%, to reach 70.8 million. That number in the same month last year was 53.3 million.

Also improving was Pandora's share of total U.S. radio listening. This metric reached nearly 7.3%, an encouraging rise from the 5.8% recorded in May 2012.

Fool contributor Eric Volkman has no position in Pandora. Nor does The Motley Fool. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.