They don't really get a lot hotter than our major heat days but our days are much longer. For
instance, 100+ degree days are not that unusual here, but they start at 5:15 and end at 9:30. Not much further north and the days start at 4:30 and end at 10 pm. That could be exhausting for some plants.
I was always puzzled by cilantro's not growing here so I did some research on it and there is a very logical theory that it just doesn't like the long days, even though it likes the heat, just not for long.
You might be able to get one round of cilantro done if you plant it early and the spring is warm. But that's it.
When it bolts (goes all rangy, flowers and seeds), just let it carry on until the seeds get large enough to harvest.
Yes, parsley works well here too. I pick parsley sometimes into December and it's back again, sometimes in late February. Arugula as well. Both are very skilled at seeding themselves.
Dill still puzzles me. Where I come from, further north, it grew like weeds in the back lanes. One would be laughed at for planting it. Here, it will do nothing. However, in the Caribbean, where one would think it to be too hot, I amazed all my neighbours by being able to grow it very successfully.