Well, maybe not booming, but I see far too many churches simply call it a year and pack it in for the summer. My church used to do it as well. From the second Sunday of June until the second Sunday of September, everything went into hibernation. The theory was that "nobody comes" in the summer. Of course they didn't. There was hardly anything worth coming to.
When I looked around at what the fastest-growing churches do, I didn't see them packing it in. Sure there might be some accommodations to a season when some families are on vacation, but they didn't just throw in the towel. After all, what percentage of your families are actually on vacation at any given point in time? I'll bet it's no more than 10% - not every family goes on vacation, most go for a week (not two or three), and they don't go at the same time.
A few years ago we adjusted our approach to summer - by treating it less like the "off-season". We're a church, not a ski resort. The result has been that we have cut our attendance dropoff in half.
The main change we made was NOT changing the time of morning worship. We used to move our normal 11:00 worship to 10:00. This created confusion among congregants, some of whom would come at the wrong time at the start and end of summer season. It created confusion in our advertising, which now can just say "11:00" instead of having a summer season disclaimer. The old-timers believed that in the summer, the earlier time allowed people to come to church before heading out to picnics or the beach. Reality check: these days, if someone is heading to the beach, they aren't coming to church first, even if it's at 7:00 a.m.
The biggest mistake I see is churches that either eliminate or curtail their fellowship time after worship. We don't cut it back in the least. We have, on average, as many or more visiting families per Sunday in the summer as we do during the program year. If that seems counter-intuitive, it's because you're used to the old traditional rhythms of the church year. But think of it from the perspective of the visitor: when is the easiest time of year to add something to your family's schedule? Summer. The kids don't have homework. Working parents aren't traveling as much for business. The lesson here is that you always have to thinking of things from the perspective of the visitor.
This doesn't mean we haven't made concessions to summer. We have soloists singing instead of a full choir - but we always have good music. I'm not planning to take any Sundays off in the summer (though this is unusual; I usually take one). But our coffee hour after worship is full-blown. We have a lot of mission activities - and in the summer, people have more time to serve.
People will lower themselves to the level of negative expectations every time. When we stopped assuming the summer would be dead time, it stopped being dead time. So next year, as you plan for the summer, take steps to make your summer schedule look a little more like the rest of your year - and your attendance will as well.