Fortunately, the evenings up here even during a heat wave are very cool, dropping back into the mid 50s at night, and the humidors all tend to drop back down to around 68 degrees by morning. So they are only at 80 degrees for about 7 hours at a time.
But I was reading on the US Department of Agriculture web site that the 80 degree reference is a MYTH. They say that the bugs can hatch at temperatures as low at 65 degrees although their development is slowed somewhat. That would seem to indicate that the potential for the problem exists for practically everyone, not just people with no A/C like me.
Historically, Seattle only gets about 25 days of 80+ temperatures spread out over an entire year and thats why most of us find it hard to justify the expense of A/C, since most of the time we don't need it.