So Shannon has posted an article about weather in games, focusing particularly on serious disaster-type weather. It's interesting, but it's prodded my brain in a different direction, which is mundane weather. There's definitely more you could do with weather than most games seem to.
A pretty big one is mood. The weather makes a huge difference to how you feel. Warm, sunny day with a faint breeze? Puts a smile on most people's faces. A cool day with a stiff wind is usually a bit unwelcome, but for a lot of adventuring situations it'll be welcome, cooling you down as you lug your own bodyweight in weaponry through the forest.
I'm inclined to think it might be interesting to apply morale modifiers for weather. Use this when considering distance travelled, social interactions, performances and other non-dangerous activities. You could use it for dangerous ones too, but players might find that a bit too much. This idea would probably work best in games that already use morale, so that weather isn't the only thing that affects it.
For example, let's take the rain.
Rain can be annoying, cold and rain is miserable, wind and cold and rain is really grim - and all those thing have a practical effect. The ground underfoot is muddy or slippery, so travelling is harder and often louder. Damp clothes cling uncomfortably and make movement awkward, and wet hair gets in your eyes. Wet ropes are nasty to handle (try undoing a tight knot on a boat rope). Cold fingers fumble, cold wet items are a pain to handle. Rest is less refreshing if you're huddling under a tree while water drips down your neck, eating cold food for want of firewood, unable to read. Loud rain and wind makes talking difficult, on top of your glumness, so journeys and activities become taciturn and lonely as you plod on.
The rain splashes surface mud back at you, and your boots (or your horse's hooves) pick up and spray mud, spattering your clothes and skin. Unexpectedly soft ground makes you stumble and slip, or leaves you six inches deep in mud. Even in town, surfaces can be damaged, water pools unexpectedly, or dodgy flagstones drench you unexpectedly. Passing cars or carts can spray you even if you were being careful, and umbrellas don't help. A galloping horse or wild animal passing nearby can spatter you with mud from head to foot.
Rain and wind can directly affect your perception, reducing visibility and blotting out sounds, but they also change your behaviour. People huddle in, keeping heads down so rain or flying debris don't get into their eyes, and focusing mostly on themselves.
Hot wet days can be just as bad. Sometimes the rain is a cooling blessing, but often it merely turns things humid. With moisture in the air, it's impossible to cool off properly. Hot damp air encourages mould. Doing anything strenuous, you rapidly get sweaty, breathless and deeply uncomfortable. Sitting still isn't as relaxing as you'd think either, and sleeping is difficult.
Changing clothes or gear tends to take longer, too. Between slippery fingers, fabrics whose friction increases as they absorb moisture, and the sheer unpleasantness of putting on wet gear, it's much more of a hassle. Maintaining weapons and armour is difficult in the wet. Reading spellbooks and preparing components is pretty challenging.
If you're staying inside, other people will have the same inclinations. Town taverns and cafes may be fuller, and those catering to travellers may have people staying longer than usual in the hope of a change. Workers may knock off early if business seems poor. Markets and other outdoor activities may be cancelled. This can be a good opportunity to make some friends or gather information. However, farmers and a few others may have extra work to do, looking after livestock or trying to plant while the ground's soft. Note that some places, such as those aimed at short-distance travellers or leisured folks, may be very empty if nobody wants to venture out. Tourist cafes fill up quickly in the rain, but parks and burger stands alike will be quiet. In less touristy places, it may only be confirmed regulars who venture into the pub or gym, and they're the best people to gossip with. People are more likely to be at home, and there'll be fewer witnesses to goings on; on the other hand, hanging around may be more suspicious. Street collectors, touts and beggars will look for shelter.
On the plus side, many insects and animals will lurk somewhere during rain. Your changes of getting bitten are much lower, even in marshland. Note, however, that very small biting insects can thrive during rain. Something for GMs to play with, perhaps.
- Consider changing random encounters and environmental hazards. Fewer mosquitos and stirges, but more flooded roads, overturned cars, stuck wagons and so on.
- Donning or doffing armour takes longer. So does making camp.
- Any work involving ropes, fabrics or slick materials becomes more difficult.
- Remember the cosmetic effects of rain and mud. Highlighting the dampness and dirtiness of everything will help add atmosphere, and can affect NPC interactions too. Some will be extra sympathetic and eager to help the bedraggled travellers into their warm halls; others may be put off.
- Consider the type of location and how its inhabitants are likely to react to rain.
- Consider whether behaviour seems appropriate for rain; if not, NPCs may take notice.
- Impose penalties to eavesdropping, spotting skulkers, and generally noticing stuff.
- Remember that ordinary activities, often handwaved, will be affected. Preparing spells or praying to deities is more difficult in miserable conditions, so ask for Concentration rolls to see whether casters get fewer spells. Hey, they're overpowered anyway, right?
- If it's hot and wet, make strenuous work more difficult. It doesn't need to be more dangerous - hot and wet is probably less of an issue than cold, or hot and dry - but you get exhausted quickly.
- Wet bowstrings, anyone? What precautions did everyone take?
- Drying out takes time. Don't forget about the rain as soon as it stops. Even when PCs are dry, it might take days for land to dry out. In some cases, it may take weeks.
Okay, that's enough for now. Might try another weather later.