I don't know that it ever gets cold enough to kill the eggs. If that were the case, Alaska wouldn't have those giant size mosquitoes it is famous for. (no political commentary, please

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I do know that most species around here hatch at 70 degrees and I've seen a few of them since it warmed up. Not all that many, though. The truck came down my street last night too. Most annoying, I had to close all the windows. I was enjoying airing out the house. It is kind of strange because the truck seldom came around during the summer, when I had lots more mosquitoes.