As I write this, the amusingly nicknamed Hurricane Bawbag rages outside, disrupting plans and causing much consternation. This time last year, of course, we were two weeks into six and a half weeks of being snowed in, so I suppose a storm isn’t such a big deal.
So... the weather in games.
Mostly it’s scenery, with dark and stormy nights aplenty, rain most often falling on noirish PIs, vampires threatened by the bright morning sun.
Sometimes it’s a dramatic device that forces adventurers to take shelter in the inn where the murder happens, or miss a vital train due to leaves on the line, or travel through Moria rather than over the mountains.
Sometimes it’s actively involved, under the control of superhuman powers for good or ill.
Games that tend more towards the dice falling where they may and the likes of random encounters might well include random weather, with a roll of the dice always waiting to screw up plans.
But a bit of strange weather could change a regular encounter even if it doesn’t fit the weather’s usual dramatic uses.
Consider a typical battle with a troop of Orcs/brigands/vampires/Stormtroopers and add enough rain to turn the ground to mud as the fight continues. Compare Agincourt in Branagh’s Henry V to Olivier’s to see the difference it can make to a standard narrative.