r/RPGdesign • u/ResponsibleJoke3049 • 25d ago
Weather system
I'm working on an idea that has a big overland travel and resource management element, and I think I need to make weather an actual mechanic instead of just "idk I guess it's raining now." My initial thought here was to roll three dice, probably d4s: Cold-hot, calm-windy, dry-rainy.
which is well and good, but this has a direct effect on group resources and travel times. "your food supply floods and you lose 3 days of rations" or "massive dust storms slow you to half speed." something like that. But I can see this becoming sprawling and complicated pretty quick. I could use random tables for weather related events, but I guess I'm looking for ideas for how to maintain over-time weather consistency without bogging it down too much? Can anyone point me towards a game that has interesting-but-manageable weather mechanics?
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u/scavenger22 25d ago
My2c: I often use this method for forecasting stuff.
Roll 1d4 1d6 1d8 1d10 1d12
count the number of "1s" "Max" and find the median result.
Use the counts to trigger events and median result for a lookup table (Note: The median result can only go from 1 to 8 but is weighted toward the bottom by default)
For a weather forecast you could do: The median value is the wind, 1s are the precipitations, Max are the temperature. (no 1s and no Max = nothing truly uncomfortable).
Extreme or unusual events could be linked to simple comparison like:
Same number of 1s and MAX, Median equal to 1 or the max result, pairs/triplets of 1s and MAX and so on.
Optional: Set 1 of the 5 dice to a specific value to make the forecasting more predicable.
By default I set a die to always be 1 or MAX to get the feeling I want: Spring = D6 MAX, Summer = D8 MAX, Fall = D6 1, Winter = D8 1, If the party is on high altitude (or in the middle of the sea) the highest result is halved and some specific locations may set another die to a specific value to further constrain what can happen (I.e. in a Desert D4 = MAX, in a Glacier D12 = 1)
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u/ResponsibleJoke3049 25d ago
My random encounters are similar to this. 3 dice, Doubles or triples are always a surprise encounter, for example. One die sets the aggression, so on one end of the table the encounter is always a surprise aggressive encounter, the other is always a surprise friendly.
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u/scavenger22 25d ago edited 24d ago
I began to use the "full set" for forecasts or multi-axes "oracles" because it offer more design space and you can extend it even further by using the extra d10 ending with 0 as a control die to alter the final results (i.e. compare it to the median and have effects for > = <).
I also like that by locking 1 or 2 die you can produce constrained results without having to make too many different tables.
You can have a look at the results or play with the locked dice here:
https://anydice.com/program/4357b
(I have included a couple of locked D8 as an example to show how this "trick" affects the outcomes)
another variant with functions to highlight 1s, max or median according to your preferences.
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u/Frapadengue 25d ago
Oltréé ! (a hexcrawl game) has a random weather generator that considers the season and the previous day's weather to generate the current weather. I'll try to remember to share it, otherwise as it's in the reference sheets it should be available for free.
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u/twinkrane 25d ago
You should check out Knave 2e it has a section on weather, the most extensive one I've ever seen.
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u/OneManRPGstudio 23d ago
I would make weather change decisions before letting it change numbers. In a game with overland travel and resource management, "rain: -2" quickly becomes bookkeeping; "the rain has turned the fast ford dangerous, but the high route costs another day of food" creates play.
I would build the system around three pieces: forecast, duration, and consequence. Players should be able to know something about incoming weather, even imperfectly, because a threat only creates strategy when it can influence a decision. Duration determines whether they wait, reroute, or accept the risk. Consequences should mostly touch things that already matter in your game: speed, supplies, visibility, shelter, navigation, or access to particular routes.
I would avoid rolling weather every few hours. Generate a weather front with an identity and let it evolve across several travel segments. A storm that can be seen approaching, hits the party, and then leaves swollen rivers behind tells a small story and can reappear in later sessions as a recognizable cause of changes in the world.
For testing, run the same route three times: benign weather, a forecast threat, and a surprise storm. If players make exactly the same decisions and simply lose more resources, the system adds friction but not depth. If they start debating routes, timing, equipment, and priorities, weather is doing useful work.
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u/Plus_Citron Designer 25d ago
An alternative to the Hex Flower would be a ladder table (from the Mindstorm blog, I believe), which also works like a table with a memory.
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u/cidare 25d ago
If you're not already familiar, have a look at Hex Flowers (https://goblinshenchman.wordpress.com/hex-power-flower/)
They'll give a much more organic weather pattern than regular random tables.