Too funny, I was going to post the same exact question today...I have wanted to figure out if they are seen more when its hot or humid or cool etc...but I haven't really even seen many this year at all...

I think you see the most on a very hot night...perhaps humid as well...but not foggy.

You might find the following firefly site of some interest. Check out the menu on the left hand side of the page, starting with 'facts about...'

I'm only seeing one lighting...er, sighting, here and there at dusk so far this year. We're experiencing extremely dry conditions though, right now -Last year was far more 'enlightning'.

Here is a link that might be useful: Fireflies (aka Lightning bugs)

Firefly larvae live in the lawn where they are predators of lawn critters. If the lawns in the area are treated for grubs, there will be a huge reduction in the number of fireflies that emerge...predaceous insects tend to be far more vulnerable to insecticides than herbivorous ones.

Thank you for sharing that, Fori. We were out just last night tracing the fireflies' light dance through our garden. Nice way to unwind at the end of the day, anticipating their next flash...and then catching up when they change course -and of course, they only seem to turn when the light's out. ;)

It's good to know the good things they do -thanks again!

I had fireflies last night!!

~Chills