A season for dragonflies....

On the subject of dragonflies, the other day we were barbequing in the back yard, when my sweet husband noticed hundreds of dragonflies buzzing about in one section of our yard. The sun was peaking through the trees and it was warmer in that section, but there was no standing water and no mosquitos within the entire block. Then we started looking harder farther back in the yard and there were hundreds more buzzing through the whole back part of our yard. It was an amazing site, as we rarely see one dragonfly, let alone hundreds. They weren't in our neighbors' yards, just ours. It was quite a site. I still have no idea what drew them here.
The next day they were gone and I haven't seen any again since then.