When to put the AC on (for a BP)?

I live in Northern NJ and own a Ball Python....so far temps outside have been pretty nice, but eventually we'll get a heat wave.

At what point are ambient room temps too high?

My Leopard Geckos can actually handle higher temps during the day (upward of 90+) as long as they get a cool down at night. Are BP's the same way? Or would running the AC to keep the room around 80 be better?

Are these snakes kept inside your house? Is there a portion that gets to 90 degrees inside? My answer would be the snake would have no where to cool off if the ambient temperature is 90+ degrees which is around the max you want to keep the snakes hot side.

You don't need to keep the room at 80*....I'd set it to come on about 86-87*, since (as I recall) that's where some breeders keep their ambient room temp. for BPs.

I think 90* is too close to the line for safety...and IF you happened to have a power failure (not rare in heat waves) then they COULD be harmed by over-heating...
you'd have no 'wiggle-room'.

You can either do 78/80 + hot spot

or mid 80's (85/86) with no hot spot

to clarify, my room will not reach 90 degrees....but when it's 90+ degrees outside, my room will definitely go above 80 degrees.

So if we get a week of 90-95 weather ambient temps will definitely rise up above 80.

You didn't mention what heat sources you are using in the cages, but assuming they're controlled by thermostats, they should (or can be made to) cut off when
the cage warms up...or just give them "a week off". When summer is at it's hottest here, I cut off most/all of my UTH for my snakes too (no BPs), just for a while.

With your house temps staying below 90 you're fine.

Your heating equipment should be regulated by a thermostat, so overheating shouldn't be an issue.

I use a UTH that is set to a thermostat...keep it at 89/90 on the Hot side.

I also use a CHE, but now that the weather has warmed up, it's no longer required.