It's not exactly 'high summer' for blooming but N poeticus varieties are usually the last ones up without intervention by a gardener. (Mid to late spring/early summer) Small trumpets and a pleasant scent. They're hardy to z3 and will naturalise.

For me, they're usually out with the Paeonies and pixie lilies.

I have had other varieties flowering at mid summer - Tete a tete and Sun Disc - but that's definitely not an annual event. The Tetes had been forced in a tiny pot and died down when I bought them - then came away in the garden again. I'm not sure what inspired the Sun Discs but, again, they were in cramped conditions.

There is some information out there on the specifically marketed as 'summer blooming' daffs... "Summer Cheer", etc., but no mention at all that you can count on a June/July bloom year after year. My suspicion is that they might revert and bloom in the spring although I have nothing to back that up. In looking around at the various mail order companies, the price seems to be about $3 per bulb.

I know here in my zone 4, if I planted any of the usual daffodil bulbs in the spring, they might develop some short foliage over the course of the first summer but wouldn't bloom. They'd fall back into the usual pattern and bloom the following spring. And with the weather here, usually with late springs, I've had ordinary daffs start to bloom the end of May and on in to June anyway.