Weather - done better

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GHench

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Generating random weather in RPGs never works that well because random tables are ...well, random. One minute it's sunshine, the next it's a blizzard.

Using a 'Weather Hex flower' allows you to generate weather that is more consistent, but still allows for some surprises:

Example image of a Weather Hex Flower:

weather-hf-cover-sm.png

In the Hex Flower example above you can see 7 days of weather indicated by the red path.

Link to PDF - Weather Hex Flower
 
Very interesting. I’ve played around with a lot of weather generation systems over the years, and it’s hard to find one that works well.

However, one thing I did was look up the weather in the Toronto are for two years, noting down temperature, precipitation, and wind speed. And, to be honest, there were a LOT of times that the weather seemed pretty freaking random. Like a week where every second day the temperature was well below the seasonal average, and the alternate days were well above the seasonal average. Or the week that there was a blizzard followed by four days of above-freezing temps with a ton of rain that wiped out all the snow. There’s more of that stuff than most people realize.

So what I did was set up an Excel spreadsheet with one row for each day of the year. I set an average temperature for each week in one column, an average number of days of precipitation for each month, and an average wind speed for each week.

Then, I went to random.org and generated 3 columns of random numbers from 1-10. For temperature, the formula was 1=average temp -8, 2=average temp -6, 3=average temp -4, 4=average temp -2, 5-6= average temp, 7=average temp +2, 8=average temp +4, 9=average temp +6, and 10=average temp +8.

For precipitation, I generated one number that indicated if the precipitation that month was going to the average number, some amount below the average or some amount above the average. Then I randomly assigned the precipitation days to each month. Sometimes I ended with a week where it rained every day, and some weeks there was a pretty good distribution, just like real life.

For wind speed, I did the same thing I did for temperature.

Because I’m running D&D 5E, I only really need to concern myself with particularly high and low temps, blizzards, and extreme wind speeds. But since I’ve got that spreadsheet, I know the weather for any given day in the campaign.

It seems like a lot more effort than it was, since I simply plugged in formulas, and then copied the list of random numbers into the correct column, which then auto-generated the daily temperatures. Same with precipitation and wind speed.

Is it a little more random than real life? Yes. Is it close enough that the players will never possibly notice? Absolutely. Does it make my job easier? Completely.
 
Interesting concept, and certainly easy to follow. But how does wind factor into it?

I use tables geared to the seasons, based loosely on Shadow World's charts -- unlike many other generators and tables, they reflect that a weather situation can last for days, and that a certain type of weather will usually follow a front. When I just want a fast determination, though, I just roll a d10 three times: once for temperature, once for precipitation, once for wind. Low = cold/lots of rain/little to no wind, High = scorching/dry/gales.

Another method I've used is this. Weather Underground (wunderground.com) is my go-to weather site, and you can plug in a location anywhere in the world and get the local weather. So if it's late summer here in New England, and I've got a party traveling in late winter, I just (say) pull up the current weather in Buenos Aires, and there we go: temperature, precipitation, cloud cover, wind.
 
Very interesting. I’ve played around with a lot of weather generation systems over the years, and it’s hard to find one that works well.

However, one thing I did was look up the weather in the Toronto are for two years, noting down temperature, precipitation, and wind speed. And, to be honest, there were a LOT of times that the weather seemed pretty freaking random. Like a week where every second day the temperature was well below the seasonal average, and the alternate days were well above the seasonal average. Or the week that there was a blizzard followed by four days of above-freezing temps with a ton of rain that wiped out all the snow. There’s more of that stuff than most people realize.

So what I did was set up an Excel spreadsheet with one row for each day of the year. I set an average temperature for each week in one column, an average number of days of precipitation for each month, and an average wind speed for each week.

Then, I went to random.org and generated 3 columns of random numbers from 1-10. For temperature, the formula was 1=average temp -8, 2=average temp -6, 3=average temp -4, 4=average temp -2, 5-6= average temp, 7=average temp +2, 8=average temp +4, 9=average temp +6, and 10=average temp +8.

For precipitation, I generated one number that indicated if the precipitation that month was going to the average number, some amount below the average or some amount above the average. Then I randomly assigned the precipitation days to each month. Sometimes I ended with a week where it rained every day, and some weeks there was a pretty good distribution, just like real life.

For wind speed, I did the same thing I did for temperature.

Because I’m running D&D 5E, I only really need to concern myself with particularly high and low temps, blizzards, and extreme wind speeds. But since I’ve got that spreadsheet, I know the weather for any given day in the campaign.

It seems like a lot more effort than it was, since I simply plugged in formulas, and then copied the list of random numbers into the correct column, which then auto-generated the daily temperatures. Same with precipitation and wind speed.

Is it a little more random than real life? Yes. Is it close enough that the players will never possibly notice? Absolutely. Does it make my job easier? Completely.
I thought about modelling weather on the real world and came up with this:

 
I just use Wolframalpha to pull historical data from a location that is representative of the fantasy region the characters are in. E.g.

 
Interesting concept, and certainly easy to follow. But how does wind factor into it?

I use tables geared to the seasons, based loosely on Shadow World's charts -- unlike many other generators and tables, they reflect that a weather situation can last for days, and that a certain type of weather will usually follow a front. When I just want a fast determination, though, I just roll a d10 three times: once for temperature, once for precipitation, once for wind. Low = cold/lots of rain/little to no wind, High = scorching/dry/gales.

Another method I've used is this. Weather Underground (wunderground.com) is my go-to weather site, and you can plug in a location anywhere in the world and get the local weather. So if it's late summer here in New England, and I've got a party traveling in late winter, I just (say) pull up the current weather in Buenos Aires, and there we go: temperature, precipitation, cloud cover, wind.
It would be easy to add a wind and indeed temperatures component. I decided that my Hex Flower was diverse enough without being too complex.

I figure regular wind only matters perhaps at sea, and only super high or low temps/wind speeds really noteworthy. All of these Can be encompasses in the extreme weather hex at the top

:O)
 
I just use Wolframalpha to pull historical data from a location that is representative of the fantasy region the characters are in. E.g.

Or you could use live predictions:

 
Interesting. One way to tune it would be to have some hexes where you linger for say 1d6 turns to make longer patterns a bit more likely if you otherwise need lots of variation.

I also had an idea for seasons. Each season (or part of a season) has it's own chart. Each chart has one or more hexes that make the transition to season if you're in the window which gives you a chance for short or long season.

I got really interested in weather when I was trying to set up a West Marches inspired campaign. Since I dropped that, I', switching to just having seasons where adventuring is strongly discouraged and not trying to do weather.

One thing I've never seen really is weather generation that takes into account things like coastal areas that are really socked in with fog and dampness for some portion of the morning pretty much every day.
 
I just use Wolframalpha to pull historical data from a location that is representative of the fantasy region the characters are in. E.g.

I've done the same thing, through a different source. If the players don't know the year and place you're using, it's unpredictable to them but you can look ahead and know what's going to happen.
 
I've made extensive use of the weather generator in the campaign calendars I've created at the fantasy-calendar website. You can even develop subregions so no matter what kind of environment your players are in, you can get a sense of temp, precip, visibility, etc., for any day.
 
It would be easy to add a wind and indeed temperatures component. I decided that my Hex Flower was diverse enough without being too complex.

I figure regular wind only matters perhaps at sea, and only super high or low temps/wind speeds really noteworthy. All of these Can be encompasses in the extreme weather hex at the top.

Wind matters ALWAYS at sea, well into the 20th century. It also matters on land, where a strong crosswind affects archery range, and winds mitigate high temperatures or worsen low ones. Ten degrees out and still air is no biggie; add in a ten mile an hour wind and that's significant wind chill.
 
Wind direction also matters for smell. Senses and detection are and important part of my games. I tend to use historical weather for a region. Essential to know the weather if there is any kind of weather prediction or control magic going on.
 
Love the flower...I'm not one put off by volume...a whole page could be interesting....with wind directions in different parts to represent weather coming in from different regions.
 
Wind direction also matters for smell. Senses and detection are and important part of my games. I tend to use historical weather for a region. Essential to know the weather if there is any kind of weather prediction or control magic going on.

Absolutely. Never mind that a factor in GMing GURPS is that game changing weather control magics are surprisingly easy to learn and affordable. My wife's wizard snuffed saboteurs torching a building, just a few days ago, by the simple expedient of dropping a 5 inch per hour Rain spell on the city block, which is a freaking deluge. (Just short of ten inches is the world record for the heaviest rainfall ever recorded within a single hour.)

Using the same amount of FP (easily achievable by a journeyman wizard with a relatively modest Powerstone), one can cast a Wind spell starting from still air to blow with hurricane force directly AT a bunch of archers, and it's cheaper to do if there's any wind, no matter the direction. Area of effect in both cases, approximately the size of a football field.
 
I often get all four seasons in one day - I might as well roll a dice before I go out of the house. When I'm gaming I just look out the window and mimic the weather - works for me.
 
Wind "almost" always matters in some way. Whether out in the sandy terrain where higher winds will drive the sand into your face or up on a mountain ridge where wind gusts can knock you right off the ridge. Or if it's dry and someone starts a fire, or it's wet and your trying to start a fire. I once had the scary ass experience of being on the Autobahn doing around 140 mph on my sports bike and came out between an opening in the mountains and onto a bridge that gapped it. A gust of wind took me from the 4th lane (the fast lane) over to the far right slow lane. Scared the living shit out of me. I've had similar experiences out in the Mojave Desert as well.

Wind should always be a factor on any weather charts, it impacts so many different things from humidity, heat, cold, air quality etc. Ask someone in Chicago how the wind impacts the weather there or those from up in Canada. You can't disregard wind speed and direction when calculating weather. I think most of you if you stop and think about it, you can extrapolate all the various ways you as a GM can have weather affect an adventuring party for good or bad.
 
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