Temperature is a factor influencing when cicadas will emerge from the earth and enter the adult phase of their lives. Cicadas like warm weather (as do most insects) and so once the soil & air reaches a temperature that pleases the cicadas, they will likely emerge. There are other factors of course, but hotter weather usually means cicadas will emerge sooner than later.
The spring and summer of 2010 have been HOTTER than usual in the mid-Atlantic area of the United States, and so species of cicadas are emerging earlier than expected. Since June first, I’ve witnessed, 32 days above 80F(27C), and 11 days above 90F(32C), in New Jersey, which is warmer than usual.
Annual cicada species like the Tibicen species and Neocicada hieroglyphica have been emerging sooner than expected. Cicadas.info has reports of Neocicada hieroglyphica, Tibicen lyricen and T. tibicen (T. chloromera) emerging sooner than expected. I’ve been hearing T. linnei in New Jersey since June.
Massachusetts Cicadas is reporting a slow start for Tibicen. Massachusetts is a New England state and is typically cooler than Mid-Atlantic states like New Jersey, but that might not be the only factor at work here. It will be interesting to see how this plays out.
The temperature will also affect when a cicada will sing: if it’s too cold cicadas won’t sing, and if it’s too hot the poor over-heated cicadas won’t sing. This is why you won’t hear some annual cicadas singing on a cool day, or when it’s near 100F(38C). This depends on the species too; some species like it HOT, and some like it cool.
I’ve also heard that temperature can affect the frequency of a cicada’s song, however, there is not a formula that allows to you determine the temperature based on the pauses in a cicada’s call like there is for crickets.