I just planted replacement hills for my SVB-ridden summer squash last week. Its the first time I've tried it, but the calendar says there's plenty of summer left in this zone. :-)

I wouldn't say it's too late. These are summer squash, right? The soft zuchini, crookneck, or patty-pan type of squash. These guys produce quite quickly and for a long time, right up until cold weather stops them. You've definitely missed alot of production, but they should grow fast in the mid summer warmth. I would expect some production in early September if given adequate growing conditions. And continue right thru until the cold temps or dark days no longer suit them, and they naturally succumb to mildew.

I'm trying it myself! I pretty much filled my garden up with winter squash (with some chard and corn struggling through the open areas), but had another area where the original summer squash planting failed (inviable seed). It took me way too long to get to the garden center and I read somwehere that you could plant zucchini until late July. So I'm pushing the envelope! We can light candles for each other. :)))