So what happens if this becomes routine? Will we just have to build all homes to have central AC like Florida?
If it's a handful of days a year, you can make do if you're in good health, anyway. One room with a window or minisplit a/c and everyone in that room will be much more comfortable than none and can be affordable if you shop at the right time.
Designing to get the right airflow, rejecting direct solar heat, and what not can help a ton with regular summer heat in the PNW. Or at least, not being totally stupid about it and making greenhouses instead of green houses. Tree shadows help a ton too, although with warmer weather, there's fire risk, and you need to select trees carefully to avoid fall risk (just say no to cottonwoods near your house, cause they like to fall and drop limbs)
https://www.epa.gov/snap/reducing-hydrofluorocarbon-hfc-use-...
Also we have to live with the fact now that the planet is significantly warmer now, and is getting warmer still. Even if we stop polluting now, there is already much damage done. Peoples life’s have been changed, and we will need to change our habits to stay healthy in this altered world. This includes more air conditioning systems in places that previously didn’t need them. Staying healthy is just as important as stopping the climate crisis.
when i moved to the PNW 20 years ago the summer had maybe a weekend or two that were hot and by hot I mean maybe 80. You would get laughed out of a room if you asked why doesn't anyone have AC.
Nowadays, nobody is laughing. The summers are getting hotter and hotter. We are IMHO at a point where if you're renting/buying/building a house AC should definitely be one of the things you must consider.