What is the best time to get a queue number for visa extension at Chiang Mai immigration office?

For the past 2 years I've gotten to the Chiang Mai Thai Immigration office for a retirement visa extension between 8:30 (when open) and 9 and received a queue number for early that afternoon and got the visa by 3.

Are you just extending a tourist visa/exemption? If so, you don't need to (and can't (well, you can, but it'll be shut and you won't get a queue number or anything)) go to Promenada the night before. As far as I know it's only the marriage/retirement visas etc. that has people going at crazy times (Tod - I know these aren't the correct terms, but can't be bothered checking what the correct terms are :P).

I haven't done it myself in a while, but I would personally always go about 2-3pm. 3pm was maybe on the late side and there was a chance of getting turned away if they were busy. Going at this time generally meant getting out again in 1.5-2 hrs. I don't think it's any faster to go in the morning, and I was definitely never interested in going there 5 hrs before it opened to be the first in the queue and "save" a couple of hours of waiting in the afternoon.

I'd say post in the Chiang Mai related groups too. Someone will weigh in.

I know people who have shown up there at 5 or 6 AM, or pay someone to wait for them because they only do so many extensions a day.

or get there around 1 pm right after their lunch break, that's what i did a week ago, was out at 3 pm.

Just get there early and you will be fine.

Early-mid morning, I think opening hours are 8.30am to 4.30pm.