Thank you so much for your help. I’ve never used the SET_TIMEZONE() function but it does the trick perfectly!
But I have a follow-up question. Apparently the value in the source field, the value that TIMESTR() is formatting, is, under the hood, a GMT value. In other words, it’s basically an absolute. Now, your formula formats that absolute value in relative terms – CST in the US. What happens if this base is accessed by another user who is, say, in California (Pacific time zone)?
To put it differently: Why is TIMESTR() adjusting things at all? I’ve got a value in the source field that’s, say, 21:00 in GMT, but I’ve asked Airtable to adjust for the local time zone, so here in Texas I’m seeing 15:00 (GMT-6). If I use a string formula to extract a value from the source timestamp, why doesn’t that time zone adjustment carry over to the string result?
I looked at the list of values that are accepted as parameters or SET_TIMEZONE() and there doesn’t seem to be anything equivalent to “Local Timezone”. Am I just missing it?