Need to get an extension at Chiang Mai Promenada. My tourist visa runs out on the 26th.
Which day is best to go? I assume monday is the busiest, so I was thinking this tuesday (19th).
(Also just making sure that visa extensions are possible on any other day than monday)
TLDR : Answer Summary
You can extend your tourist visa at the Chiang Mai Promenada any day from Monday to Friday, excluding lunchtime from 12:00 to 13:00. It's recommended to avoid Mondays due to potential busyness, so Tuesday (the 19th in your case) should be a good option.