Right before the turn of the millennium, President Hinckley rolled out a new temple-building campaign that reimagined what a temple could be. The Church began building temples that were far smaller than their predecessors, but were also much closer to where members lived.
It has been a couple of decades since then, and President Nelson has his own slew of newly-announced temples. I don’t think he’s made an explicit point like President Hinckley did, of saying they’ll be smaller. I think the sizes are clearly varying by location.
I got to wondering how much of the temple capacity of the Church is still in Utah, or still in the US. My impression is that even with many of the small Hinckley-era temples being built in the US, there are still often quite large temples built here, even in the Mormon corridor. Look at Payson, Utah (dedicated in 2015), for example, or Gilbert, Arizona (dedicated in 2014).
To answer my question, I looked on the Church website at how many endowment sessions there were in each open temple, and how many seats were available in those sessions, for two dates in February: the 14th and the 25th. I checked the number of available seats at least a month before the session dates so that few would be likely to be scheduled. I chose these date to have one weekday and one Saturday, and to not be right next to each other, so a temple that might be closed for cleaning on one day, for example, might open back up on the other. Also, I chose to look at endowment sessions because they’re by far the most time-intensive of vicarious ordinances, so they’re the biggest potential bottleneck.
There are 161 temples with at least one endowment session on February 14th or 25th. (I did notice that a few temples that weren’t listed as having sessions available when I started gathering data did when I checked back in the last few days, so it’s possible that a few more will open between now and then so I may be undercounting a little.) Here’s a breakdown by region.