Farenheit 104 (40 degrees C). This is a number everyone should know.

[susanna]

16. So glad to hear this as a gardener...

Three things that made me a believer in the biggest way (I'm in Detroit, pretty far north). And, for the record, I've been gardening for thirty years, gaining knowledge along the way. Here are the biggest differences (and this is not the complete list):

1) My rosemary survived for the very first time this last winter. This has never happened. Always a goal (mulching, burlap, planting close to house), yet seemingly impossible based on our snows and hard freezes. Evidently it can survive. However: I didn't protect it at all this past winter; I'd given up. Let it go. It came back.
2) My mint has died immediately once planted the past few springs. That plant is a weed, to me, and will take over anything it can; I've never lost a crop until recently. It just can't handle these current temperatures. I've grown it forever and ever, successfully. I just now realize that I'm not a bad gardener because of this failure.
3) I grow beautiful lavender in DETROIT. Stunning, it is. Have only been able do it in the last six years or so.

As an interesting sidenote: I also have a new weed that I have never seen before (I'm 45) in my gardens, anywhere in this zone. It chokes everything it grows near. Luckily it's shallow rooted, but...I have NEVER seen it before, in 30 years. Where did it come from? I spend half my summer yanking it (don't believe in herbicides).

Based on the above, I understand what you're saying. I have to readjust what I know about growing green things. NOT easy. I'm often at a loss...