Best city for Summer in the USA.?

According to my opinion, San Antonio, Texas is a best city for the summer season.

San Diego year round. So in the summer you'd rarely get hot and muggy weather. High 60s and low 70s are common in the summer. Air conditioning not required. And the beaches are great. Silver Strand is unique in that the beach lines both the Pacific Ocean on one side and the SDO Bay on the other.

I'd stay away from any city east of the Mississippi River as they are all pretty much hot and muggy. You'll sweat a lot. I lived in Ohio, Maryland, and Florida; they were all hot and muggy in the summer.

Oh...Monterey CA is also a great summer retreat. It's a small town with a big town attitude and things to do. And a huge beach on the Bay and parks. The famous Pebble Beach Golf Course is there and the formula racing Laguna Seca is also there. And like San Diego, the weather is cool and dry. Again no AC required.

San Diego. And up the coast to Santa Barbara or so.

Summer session? For vacation?
Chicago has great weather, lake, beach, pro sports, museums, concerts, festivals, shopping.
There are plenty of towns along the east coast that are Great.
New Orleans- although hot and humid
Washington DC

Traverse City, Michigan

Depends on what you're looking for. Anchorage is great to get into cooler weather. Lake Tahoe, Flagstaff is perfect time of year if you want to see the Grand Canyon. Seattle, San Francisco also nice during the summer. I'd avoid places like Phoenix, Vegas, and Miami.