We have a French Cafe (not Jewish) inside the “Eruv” which has several tables outside. Sunday evening they were empty. We ate inside. Monday after davening I walked by and several people were eating outside. Hence, the day Seudah was in the Sukkah.
Back to the French Cafe: My best guess is that the Eastern Europe branch moves all the tables inside by mid September. The outside tables would always be busy in Bavel, unless it was actually raining.