What time period does your nation take place in

[Savroyska]

1993, during the Third World War.

[Al Halatbah]

In the 1840's, right in the midst of Al Halatbah's industrial age.

[Greenwichian Arcadia]

Exactly 50 years ago, but with more-or-less modern tech and slightly ‘outdated’ cultural tastes (around 80-90s, I guess).

[Insignias]

We’ve been going strong since 17 AD, But it’s currently 9595 AD.

[The Sherpa Empire]

It's heavily influenced by my memories of living in China from 2005-2007, so basically modern-tech, but some things are slightly out of date.

[Broader Confederate States]

2065 CE, though you're much more likely to find people, even those non-religious, to use AD instead if they even have a reason to specify.
However. And this is a big however. Society more or less hasn't gone too far past 2027 and in many ways has regressed, due to the mounting 21st-Century oil crisis. January 31, 2027 is the day the United States of America enacted its oil rationing policy, and only a decade later, it nearly caused a second (some would argue third, or even fourth) civil war before the three regions decided to split apart. None of them resumed the old oil habits of the 20th and early 21st centuries. However, things are kind of going alright, due to the South's abundance of nuclear power plants and its newly built torrefaction facilities for rail transport and some power generation. Automobiles are prohibitively expensive and looked down on, and most people take rail transport due to it being cheaper. Airplanes are pretty much gone except for inter-continental flights. Renewable energy does have a small place, especially among those who use CRT computer displays or televisions (you're very likely to see a solar array, small windmill, and battery system on those people's houses) but they're not frequently used on a municipal scale.

[Ko-oren]

Roughly around today, but time goes by a little bit faster. Before long Ko-oren is a few years to decades ahead of the current time, but still with the same tech as RL.

[Yawkland]

Yawkland is currently set in the 1960s.

[Aldina]

Aldina exists in a constructed setting that doesn't directly correspond to any real-life year, but generally resembles the first half-ish of the 20th Century.

[UniversalCommons]

We currently exist in many timelines. These timelines exist in multiple dimensions. Time is an infinite sphere of fields and we probably are in a field that represents the past, present, or future. Since the past, present, and future have already happened, we can move to any particular thread in the forum which we desire. Sometimes this causes different variants of the Universal Commons on different timelines or threads. This is not inconsistent, it just shows that time has branched in a new way allowing us to exist in multiple different realities, or worlds. Thus there are many different variants of the Universal Commons happening at once.