im in south carolina and the temps in the day are around 70 but last week they were in the 80s the nights were like 55-65
the soil was out of a bag that had been in that pot for like 2 years with nothing growing in it
I thought at first they looked like they'd taken some cold damage, but from what you say, your temps haven't been low enough (would be more like mid-30's). Looks like you may have a disease on your hands. Potting soil is not sterile, like seed starter soil.
What you could do, to test that theory, would be to pinch off the affected leaves on a plant or two, and if all the new leaves that grow out have that spotting too, you've got disease. I would then toss them if it were me (and not into the compost pile, but far away/or burn them so it won't spread to anything else).