This week, temps are supposed to reach as high as 110°F. As I write this, several of the LED streetlights are dayburning. I have no idea why they are, but unless the city fixes them before the crazy heat, there may be millions in losses of having to replace the destroyed lights.

What do you think will happen? Will the lights be unaffected? Or will they be totaled and have to be replaced at $400 per luminaire?

For one or two days it should not be a problem (decent designs contain thermal protection, which should prevent an immediate danger by either reducing the power or shutting down completely). However if they want to keep it like that weeks, it will definitely affect the reliability (those protection is designed to handle sparse events, not systematic overheating).

I sure hope Florida doesn't get that hot.

Day burning is likely a result of a shorted out photocell.  If they did not replace the photocell and reused the old one off of the fixture the LED replaced, then chances are, after a storm, some water got into the photocell and shorted it out.  Thus it's day burning.  And the LED will be just fine.  Don't worry about the hot temps.  They use these Philips LED fixtures down in Arizona. 

Results:
The freeway LEDs that are low-power and large survived. (most of them anyway). There were some Cree XSP lights that were dayburning near here. 2 survived, and now the rest of them are out or are barely working (1 LED is lit in them). They don't come on at night even so I am pretty sure the heat killed them.