Weather and other Random Generations

Loonook · May 9, 2012

Denizens...

So I actually was really intrigued by a recent article on Gnome Stew about generating a Year of Random Weather..

And so I tracked down the Dragon Article (Old Archives CDs ftw!) it is based on (Dragon 137, p. 34-42)... And have come to the realization why AD&D numbers always feel weird.

Random Generators don't get a lot of testing

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So for my own sake I generated a basic climate worksheet based on this system using a simple warm/wet climate... I've confirmed all formulae, all systems-based information, and hacked the thing up out of nothing for complete random generation.

The system isn't really too random, or doesn't have the feel to me. I've run about 10 generations of the material through day to day and the information doesn't seem to be gelling.

So I have decided to ask the few, the proud, the analysts among us to help me out.

I've put up the numbers up in a sheet, only changing a single set of variables (increase the range of temperatures by 2 degrees on either side for a little blending of cooler/warmer season variance)...

Run the numbers ten or fifteen times. If you alter the sheet in any way it will immediately regenerate and I haven't locked it so when looking through be sure not to do much to it

.

See what you think, and if you can please post I'd be happy to hear you.

Slainte,

-Loonook.

Janx · May 10, 2012

interesting approach. Not the way I'd do it.

In the past, my approach to weather is that the present is based on the recent past.

So today's temperature is plus or minus a random amount from yesterday's temperature.

Similarly with precipitation. Though in real life, if you didn't know about weather, you could swear it was random whether it would rain tomorrow, regardless of if it was raining today. Consider it from the perspective of somebody who journaled whether it rained or not, and how much each day. Yesterday didn't make much difference to what happens today, because the bigger picture was determined by the size of the rain cloud above you and how much it moved.

So, from the perspective of people who have no weather channel or ability to see cloud patterns beyond their current position, you can model weather from the perspective of "where you are right now"

For that consideration, imagine we all live in Hereville. It's a moderate climate town, it has the normal four seasons. It rains, it snows, it's sunny some days, cold on others.

We can model the "current" temperate based on a sine curve spread across the length of the year and scaled to the temperature range extremes (let's say 100F to -40F like my native homeland). I'm not a math guy, so I'd have to look that up. Hopefully you know what a sine wave looks like.

Anyway, that would give you a standard temperature for each day of the year. Apply a 1d20-10 modifier to whatever the standard temperature is for today. This will make the actual temperature for this day of the year different from past years and cause some fun variation from day to day.

If we want to get really fancy, we'd model temperature on an hourly basis and wire it up to a sine wave function (it gets hotter in the day, cooler at night). Once again, apply a randomizer to make it shift a bit, though not so dramatic as before. a 1d4-2 modifier would probably be sufficient. It's common enough to see a shift from 60F in the early morning to 80F or more by late afternoon and then it drifts back down as it cools.

Next up is precipitation. From a narrow perspective, if it rains hard today, it may or may not rain tomorrow. So work out the percent chance of rain as is typical for that area and season (tie to to the standard temperature), and you'll get close enough results.

If you generate a year at a time, you should see trends and multi-day weather commonalities that you can describe in game as clear skies, big storm systems, etc.

that's how I'd approache it.

Hand of Evil · May 10, 2012

Farmers Almanac - more information than you can shake a stick at! Need to know the tides, the summer solstice, weather, sayings, puzzles, what is in the sky...

One of the great books to take information from.

Janx · May 10, 2012

Hand of Evil said:
Farmers Almanac - more information than you can shake a stick at! Need to know the tides, the summer solstice, weather, sayings, puzzles, what is in the sky...

One of the great books to take information from.

yeah, the weather from last year for a place analogous to where the PCs are is probably random enough.

FickleGM · May 10, 2012

For some reason, I'm still a big fan of the 1e Greyhawk weather generator. It just worked for me.

Loonook · May 10, 2012

FickleGM said:
For some reason, I'm still a big fan of the 1e Greyhawk weather generator. It just worked for me.

Have you seen the Excel that generates a full calendar for the Greyhawk Weather Generator?

Yeah... That's pretty much using the same backbone as this generator and most of the same charts... Which are most of the ones in the Weather Generator system

.

Slainte,

-Loonook.

FickleGM · May 10, 2012

Loonook said:
Have you seen the Excel that generates a full calendar for the Greyhawk Weather Generator?

Yeah... That's pretty much using the same backbone as this generator and most of the same charts... Which are most of the ones in the Weather Generator system .

Slainte,

-Loonook.

Nice. I approve. I might not get a chance to check out yours until Monday, but I definitely want to when I have the time.