Checking the d4-cast

This one is about weather. Let's talk about it.

Recently Josh wrote up a really cool table-with-memory post, demonstrated with weather, over at Rise Up Comus.  I love a random mechanics with memories, and I will get up to all sorts of fun with this Stepladder Table. But in reading the post, I came across a phrase I have read countless times. In one way or another, it's in almost every O/NSR game I own* that concerns itself with atmospheric conditions...

"Roll 1d6 every day for weather," after which you consult a table to determine the results. 

It's simple, it's fast. I get why this is the standard. I've used it in a lot of games, including my own hack. And it was in the most recent playtest of said hack, wherein the players ventured through the Black Wyrm of Brandonsford, that I finally was able to put my finger on where this standard weather mechanic falls short for me.

Assuming the table has six different results, it's absurd that there is only a 2.78% chance the weather will be the same two days in a row. Let's go even further: there is a 0.46% chance it'll be seasonally nice weather for three consecutive days. Does this reflect your lived experience when stepping out your front door at all? Does anyone else look at those probabilities and go, "you've gotta be joking me?"

Listen, I know that elfgames are (usually) set in fantasy worlds and going down a rabbit hole of "but this is how it works in the real world!" is madness. On the other hand, part of the reason the genre works is because you have fantastic elements alongside the familiar. And ricocheting weather isn't the kind of fantasy I'm interested in bringing to my tables. There simply has to be another way. So here's one:

Checking the d4-cast

Like Josh's aforementioned post, I'm sure this has been done before. In its simplest form, you roll d6 to determine the weather, and then roll a d4 to determine how many days it persists. Now you have a 6.25% chance of one-day weather two days in a row, and a 1.56% chance of it happening for three days straight.

There are definitely some issues I'd have with following this blindly, but rules are tools so let's make this one work for us in an example. 

Summer Weather
1.Thunderstorms, high winds
2. Showers, overcast
3. Partly cloudy, gusts of wind
4. Sunny, cool breeze
5. Sunny, humid
6. Sunny, sweltering heat, high humidity

Now let's look at a week's worth of weather, using Monday-Sunday.

Monday: I roll a d6 for weather and get a 3 (partly cloudy, gusts of wind). I roll a d4 and get a 2. It's looking okay today and tomorrow.

Wednesday: I roll the weather d6 and get a 5. I d4-cast it, and it's a 1. One day of sunny, humid weather.

Thursday: The d6 comes up as a 1, the d4 a 3. Three consecutive days of thunderstorms seems a bit excessive, so instead "thunderstorms, high winds" becomes the destination we'll reach on Saturday. Today and tomorrow are steps leading to it. Storms often follow hot/humid weather, so let's say Thursday is 6 (sunny, sweltering heat, high humidity).

Friday: The next step in our arrival to the storm. Maybe the edge of the roiling mass of storm clouds reaches us today, and we have 3 (partly cloudy, gusts of wind) as a sign of things to come. It is probably still really hot and humid since the storm hasn't come to break the swelter.

Saturday: The storm arrives. Rejoice, storm-loving freaks! Me personally, I can't stand 'em. 

Sunday: I roll a 1 for weather. I don't even d4-cast it. Sure, I could move it up to 2 (showers, overcast) as we get the tail end of the storm cell passing through. But, this is a golden opportunity to embrace the 90s and GO XTREME. Yesterday was just a normal thunderstorm. But today? Today is the center of a massive storm cell. Tornado-warning conditions. Today is fallen trees, golf ball-sized hail, roof-ripping winds. Welcome to The Big Storm of the Summer! This is why I hate storms: inconvenient at best and downright dangerous at worst. At least tomorrow will be nicer!

Well there you have it. A little pyramid-shaped addition to determining weather. I do have some more complicated ideas on the subject. Maybe that'll be a future blog post.

*Looking at you, Errant.