When will FL vote to the left of PA

[Skill and Chance]

Maybe next election, given current trends.

I'm not sure about this.  If anything, Florida appears to be moving right.  Pennsylvania is as well, but it seems like the easiest 2X Obama-Trump state for Democrats to win back.  For now, the influx of retirees and final decline of the anomalously Dem FDR generation is clearly winning over ethnic diversification.  It also doesn't help that Obama decided to pal around with Cuba.

The Puerto Rico situation could change this, but the only way I could see it happening in 2020 is if PA swings hard right like Florida did for Bush in 2004.

[Skill and Chance]

2024 or 2028.

Old white retirees won’t be flooding Florida in the same numbers they have been if these hurricanes continue to intensify. They’ll begin to retire to other places.

I wonder where affluent retirees will go if the sunbelt becomes a mess thanks to climate change? Maybe New England?

Well the Sun Belt metro cities aren't entirely along the coast. Sure there's Tampa, Miami, Jacksonville, and Houston, but there's places like Raleigh, Charlotte, Atlanta, Orlando, Dallas, Austin, San Antonio, and Phoenix that are all inland. My guess is that retirees start migrating to warmer but more inland places if the storms become as frequent as they have been this season. People don't want to risk property damage, especially if they're in retirement. I'd guess other southern areas with lakes and golf courses galore or something like that become more common.

I wonder if that could actually end up causing a state like North Carolina or Georgia to shift back to the right?  That would be an interesting development.

Influx of Puerto Ricans could cause Florida to shift to the left, while a shrinking Pennsylvania drifts to the right.

It is an incredibly recent thing that a growing area would be more Democratic than Republican; I wouldn't count on that continuing for TOO long.

This is already what's keeping the GOP alive in NC.  I think it would be dominated by other trends in Georgia, though.  Not to mention that both are quite far south and NC has been whacked by quite a few hurricanes in its history.  If environmental conditions in Florida deteriorate, I think you would start seeing retirement communities spring up in the Western no income tax states (NV, WA, SD, WY, maybe TX but it also gets bad hurricanes, AK if the climate really warms).