if you can think of it...you can program it. That's what I am told by the programmers where I work at least.

The basic macro things related to seasons shouldn't be too hard to implement. It wouldn't be very hard to put status effects on characters and regions based on the seasons, though individual storms and the like may be a too specific to be balanced properly.

Looking at the screenshots, I think a turn is a day, as research on there is given in days.  I wonder if this will be configurable, though...

A weather system is a big project to include within the game, if it's not currently planned I doubt it could be included.

I'll advocate it if you won't.

Just think how cool it would be to spot a storm front approaching the mountains and knowing that if you can lure your enemy onto the windward side in a few turns, there's a good chance they'll get stranded in a blizzard while your troops take cover in the forest below.

Dynamic weather could be a good way to add an element of timing to the players' battle plans, much like terrain bonuses heighten the importance of location. Heavy rain might slow the movement of siege engines on open ground while greatly reducing the range of archers, which would be bad news for any large troop columns on their way to siege a city. Snow and cold would be hard on mounted units and melee fighters, especially at higher elevations. Fog reduces visibility in valleys, wind makes physical and magical projectiles less accurate but speeds flying units, etc. Could make things interesting. Certain locations might even have recurring weather patterns, like an often-flooded river or misty swamp.

I like the idea of weather as "atmosphere" in the vibe sense, and as a factor in the economic layers, but not so much as a combat variable. At least not without a really good "fog of war" function that meant you had to have a fantasic info network or some serious weather magic to know what's coming down the pike.

If there is a weather system, I trust it will be scalable for the big maps so there are places where blizzards are impossible and others where droughts are unheard of.

But most of all, I don't want to see this game setting end up sounding or looking like it is a goopy, gassy lump of rock whirling around a fat wad of fusing hydrogen. I know this thing has associations with the GC stories in Brad's background work, but I'm hoping that Elemental all takes place before (or at least beside) the Big Bang that created the universe of the Arnor.

I think it may be a bit difficult. Weather is probably something you want to animate in real time, but the game is turn-based. So, it could be a bit jarring when the weather changes.

Weather system would be nice if it was localised because it would open up the possibility of weather spells. If one could continuously cast draught on an area and cause it to dry and become unproductive for instance. Or other more or less subtle effects to ruin your opponent's land (yet another thunderstorm).

Oh yeah. Cast some fog over an open field so your swordsmen can make it across without being massacred by archers, or cast drought to dry up a riverbed so your siege engines can cross. But if the spell isn't powerful enough, or if the normal weather pattern is too strong, you might not get the effect you were expecting...

While a full weather system may be too much, seasons should be doable. They can alter the general look of the map (a series of filters) and convey a global bonus or malus. For example, in winter, all cold-blooded units might be at a disadvantage.

Dominions 3 has this system (complete with random events particular to each season), and Dom3 is what I see Elemental competing against.