I have a flight leaving Swampy at 5:40am headed to the US. So, I would need to exchange about 100,000 baht into US$ at about 4am. Would I be able to do that at that time of night?

Also, I did a search and read one poster who said one would be able to get better rates in home country (in the poster's case, Oz, in my case, US). If that is the case, I will just wait until I am in US since I have a couple of hundred US$ to carry me over the arrival period.

Thanks in advance for any help.

Plenty of booths open 24 hours spend the night there for a flight last month and never saw a closed booth.

For the rate I think the airport rate will be the better than in the US, if you can exchange in town if possible.

There's no need to change such a large sum at the very last minute is there? Work out what local cash you need for last-minute eats, drinks and other purchases and change the rest during regular hours at a money changer. Stress-less.

Do change some in town if you can. Rates at the airport, while not horrible are definitely measurable compared against rates in town. Change up 95,000 the day before and keep 5,000. I like to take some baht back home with me anyway, just so I will have some pocket money, bus fair, quick food money etc the moment I land.