1 turn = 1 day
According to the Elemental screenshots that have been published so far, one turn will be one day.
I was just thinking that this would have some undesired consequences.
Age of Wonders had the same system which meant that you could build a Temple in 4 days or maybe a Stone Wall around an entire city in only 2 days.
Galciv2 suffers from the same problem where one turn is one week. This basically means you can go from an early spacefaring civilization to the ultimate technology and Ascension in only a few years; but since this is Sci-fi it's somewhat more acceptable (who really knows how future technology progresses). Population growth is also quite an issue in Galciv2 for the same reason (billions of people popping up in mere months).
Galciv1 was better in this aspect with one turn being one month.
Master of Orion II did it even better as it didn't specify how much time a turn represented. It only had the undefined 'Star Date' which could really mean anything.
In Master of Magic each turn was a month (even though it wasn't evident from the main interface).
Furthermore, a game of Civilization IV lasts from 500-1500 turns depending on what settings you choose. It can be even shorter if you win before the time runs out.
If we apply this to the '1 turn = 1 day' system, then a full game will last from 1,37 years (500 days) to 4,11 years (1500 days). Not very epic if you ask me. How do you build an empire (from scratch) in only 4 years?
Of course, a game of Elemental might last tens of thousands of turns and a Stone Wall may take 700 turns to build. However, I don't think that will be the case.
If we on the other hand use the '1 turn = 1 month', then a full game would last from approximately 42 years to 125 years. That has a much more epic feel to it.
Of course this opens up a whole new can of worms.
It will take months to travel from place to place (not really that unrealistic).
Your wizard or heroes might die of old age; but then again, I wonder if a master wizard hasn't got a few tricks up his sleeve to help cheat death and his essence might also protect his heroes.
I'm sure there are lots of other problems with this model and maybe it would be best if a turn is just an undefined amount of time. So instead of writing "Days" or "Months" on the interface screen, just have it say "Turns".
So what do you guys think? Feel free to convince me that "day" is the best solution, I just want to be happy with the game.