I don't really do conculturing - Vetela is just a personal language that I work on for the fun of doing so, and isn't supposed to have any fictional group of speakers. However, the one small area of slightly pseudo-cultural stuff that I have added to the language (because I think it's interesting) concerns the observation of certain astronomical phenomena and waypoints in the cycle of the year.
The Vetela calendar is an alternative way of measuring the passage of the year, which is linked to the moments of the solstices and equinoxes (collectively known as nyuka in Vetela[0]). The four nyuka days have special names: Leetas, Mekia, Lantas and Vynyma (these are proper nouns and don't have any particular etymology, though the words do have ideophonic associations for me). The periods in between these are known as Vaileta ("ascent"), Akoyna (from akoa "hot"), Vauleta ("descent"), and Leskyna (from leska "cold"), and are divided up into sections according to a system that I may explain in more detail in a future post. So yesterday was 4-23 Vaileta, today is simply Mekia, and tomorrow will be 1-01 Akoyna.
Leetas is always the first day of the year, so there isn't a regular schedule of leap years - each year is as long as the number of days between consecutive Leetas days, which is always either 365 or 366, but doesn't vary in as simple a pattern as the Gregorian leap year cycle. (It is however entirely predictable of course.)
Another thing to note is that, since this is essentially an Earth calendar and also doesn't deal with anything smaller than a day, timezones just work as they do normally, and all calculations are based on UTC. So since today's moment of solstice occurred at 05:04 UTC, the 21st June 2013 is Mekia, regardless of timezone. This means for example that, in the PDT timezone, the actual moment of solstice occurred yesterday on 4-23 Vaileta (20th June).
Pronunciations:
nyuka ['nɜu̯kɑ]
Leetas ['ɫɛ:t̪ɑs], Mekia ['mɛkʲ:ja], Lantas ['ɫɑn̪t̪ɑs], Vynyma ['fənəmɑ]
Vaileta ['fai̯ɫɛt̪ɑ], Akoyna ['ɑko.ənɑ], Vauleta ['fɑu̯lɛt̪ɑ], Leskyna ['ɫɛskənɑ]
[0] If I were to create a conculture one day, the nyuka would probably be national holidays. :)