This is an Eastern Tiger Swallowtail (Papilio glaucus), a North American native butterfly species. I believe the Buddleja upon which today’s garden visitor is feasting is Buddleja davidii ‘Adokeep’ (Adonis blue butterfly bush).
One weather source gives the temperature as 88°F (with heat index it feels like 101°F), but another reporting station shows 92°F and my money is on the 92°F. Last year the actual high was 99°F. Thunderstorms are predicted for later this evening. They have been regular occurrences lately.