Many time-based calculations in Airtable are made using GMT. However, after running several tests, it appears that the “yesterday” option works as expected when a date field is set to local time. So even if the GMT version of the time isn’t yesterday, it will be seen as yesterday as long as the date field in question is not set to display the time as GMT.
However, these initial tests were run with an actual date field. If the date field being checked by your automation is a formula field that outputs a date—e.g. you’re using
DATEADD() to calculate a new date based on an actual date field—it will behave differently. As an extension of my test, I made a formula field that did a straight copy of the date from a date field. Both fields were set to not use GMT to display the results, and yet the formula field showed a date that was one day earlier than the actual date field. However, the record with a matching “yesterday” date in the date field still triggered the automation using the formula field even though the displayed date from the formula field was two days prior, not just one.
The fix to get this formula field to display the correct date is to turn on GMT option for the field. It may seem counterintuitive, but it works.