The Georgia emissions inspection testing program hours and schedule is dependent upon which testing location you are planning on attending. You can see a list of the different locations HERE and call the location you are going to bring your vehicle to for emissions testing to see what their hours are. Most emissions testing locations are closed on holidays.
There are some tips for you in order to avoid having a long waiting for your emissions inspection. You should try to come at an offpeak time. Peak times are before and after work and during the lunch hour. Other times would have significantly less wait time. You should also try to avoid coming the first few or the last few days of the month. These days tend to have higher traffic and emission inspection wait times can increase. The middle of the week has less traffic.
You can call the emissions testing inspection station you plan on attending and ask them to recommend the best time to come in. Some stations may also allow you to schedule an appointment so you can ask them if that option is available. You can find a large list of emissions inspection areas in Georgia on this page.