I've only experienced the 17 periodic cicadas ONCE in my entire lifetime... it's something you're not likely to forget!
At fist I thought it MUST be some sort of Machine! ...a GROUP of industrial-strength LAWN MOWERS(?) But the sound was far too throbbing, undulating and unified to be either mechanical.. OR Alive!
. Yeah... the 17 year periodic ones come in batches... the last batch failed to make a showing in 'Jersey a couple/few years ago... So far it's a no-go here as well.
I read that they won't poke out of the ground unless/until the SOIL Temp. is a CONSISTENT 70F.
So far EVERYTHING Here in the North East has been over a MONTH LATE. Yes, that makes a HUGE Difference since they're not the only insect or crop dependent upon an exact number of days at a precise temperature.