I know there are tons of more complicated and in detail charts to use out there, I still own a pristine copy of the Wilderness Survival Guide and have just about every printed Dragon Magazine since issue #50 proudly displayed on the shelf in my basement, however I also like my game to flow and having a book of charts and tables to refer to so often and not get any real material worth out of them just seems crazy and bogs the game down.
So I use a simplified weather system in my world.
Type of Weather (d10)
1-3 Sunny day (with 3 being a few passing high altitude clouds)
4-6 Cloudy day (with 6 being a threat of rain/snow/storm)
0 Something special
And Temperature (d6)
1 15 deg F cooler
2 5-10 deg F cooler
5 5-10 deg F warmer
6 15 deg F warmer
That’s it. The system is simple, sweet, and easy. No odd charts, it’s off my head and memory, and I move on.
Now some of the nitty/gritty/detail sections.
The area the party is in now is roughly the same latitudinal location as Georgia, North Texas, or lower California (sorry for the USA-centric positioning, I am a native of the country – Let’s call it 32 degrees North). This means that in the depths of the seasonal months (Feb, May, Aug, November – Winter, Spring, Summer, Fall respectively) I use 35, 60, 85, 60 as the normal temps. I’ll drift that number accordingly 5 degrees from normal for each month in the equinox season, and 10 degree swing for each month in the vernal/autumnal season.
WTF does that mean? Lol. Easy explain:
Jan 40 Apr 50 Jul 80 Oct 70
Feb 35 May 60 Aug 85 Nov 60
Mar 40 Jun 70 Sep 80 Dec 50
This means that I can have in Feb a day where the temp can swing wildly between 20 degrees and 50 depending on the dice roll and it makes sense since most of them will be 35 degrees. That helps when I check for snow/melting if there is any on the ground and I don’t need a chart. Remember – these weather systems are supposed to be easy and easily remembered on the fly without having charts or complex systems or tables in place.
The area that my group was in last time was much further north, latitudinally the same as North Jersey, Central Pennsylvania and the like (Call it 40+ degrees North). So my seasonal month temperatures were a bit different: 25, 50, 80, 50. Colder winters and seasonality, and the summers were only a bit off.
The difference between the two areas means/meant that for the first grouping, 5/6 days were cold enough to have snow and keep it on the ground with only infrequent melting. The second grouping has a different swing of things with only 1 or 2 tops out of 6 days being cold enough to generate frost/snow.
I mention it because the party has been doing a lot of travelling lately and the weather, state of roads and ease of travel is pretty important right now and they have been in situations (before) where there were freak snow squalls that gave 2 feet of precipitation.
And that leads us back to the 1st chart/random numbers – the type of weather and rain/snow.
To see the type of precipitation, again the handy d6 comes out with: 1-3 light, 4-5 medium, and 6 – heavy.
Again – WTF does that mean?
Light – Drizzle on and off, maybe a brief but sudden summer type storm – lots of rain but short. Overall the total accumulation hovers between annoying and getting wet. Rainfall for light is between 1/10 inch and ½ inch. If it is snow – it’s between 1 and 5 inches.
Medium – A regular rain storm. It comes in and rains all the day. Great for plants, not so good for travel unless you like mud. Rainfall runs from ½ to 1 inch. If it’s snow, between 5 and 10 inches.
Heavy – A serious soaking. You are going to wet and miserable. Baladrana’s will give up the ghost after a few hours and expect to make a sickness check. Hope you have extra clothes and underwear since you are going to be unhappy without it. Rainfall runs 1 to 2 inches. Again, if snow, 10 to 20 inches.
Snow is 10x the accumulation as rain – easy to remember. As for qty, you can hand wave it or a d5 (d10/2) gives you your total for the day.
And that brings us to the “0” on the chart – Special. All random tables need a special. And for that I pull it out of my hat. I have had freak storms that drop 26” of snow, heat waves that spike the temperature up 30 from base or cold snaps dropping the temp the same amount down from normal. Hurricane? Sure! Tornado touch down? Why not! The long and short of it, anything that seems like it would make sense OR I haven’t had/done in a while comes up on that magic roll of “0”. Could I make a chart and plot some stuff out? Maybe, but it defeats the purpose of the way I do it, and that is to keep the game flowing, have some sort of logic, a viable and easy to use weather system, and keeping it simple.