The Unseen Servant forums

As I have stated elsewhere, I prefer to leave as much as possible in the games I run up to the vagaries of the dice. A while back I started randomly determining weather at the beginning of each game day and came up with some tables to determine random weather. I have been asked on occasion how I determine weather, so thought I would post those table here for anyone interested.

Please note that all of the below tables are designed to be modified by both season and climate. So, if the climate is arid, one might increase the chance of clear weather and decrease the chance of precipitation. A tropical climate may do the inverse. Likewise, it is possible that in an area with a defined "rainy season" there may be an increased chance of precipitation during that time. The chances of these tables are designed to simulate average weather in the current location of the game I am running.

First, we roll a d20 to determine Clear or Cloudy as follows:

1-10 Clear
11-20 Cloudy

A result of 1 or 20 on this roll indicates a special condition (see below).

If the result is clear I roll 1d20 again:
1-15 Clear all day
16-20 Precipitation within 24 hours (I roll 1d24 to determine when this precip. will occur, from midnight)

If the result is cloudy I roll 1d20 again:
1-10 No precipitation
11-15 Precipitation within 24 hours (again, 1d24 to determine when, from midnight)
16-20 Current precipitation.

If there is precipitation roll below:
1 Storm, violent (6d6 hours)
2-4 Storm, moderate (6d6 hours)
5-7 Storm, mild (6d6) hours
8 Storm, violent (1d6 hours)
9-11 Storm, moderate (1d6 hours)
12-14 Storm, mild (1d6 hours)
15 Storm, violent (3d20 minutes)
16-18 Storm, moderate (3d20 minutes)
19-20 Storm, mild (3d20 minutes)

I've also got some tables for the chance a storm includes thunder and lightning, as well as average precipitation. Note that for the most part these results simply add atmosphere and have no game effects, although a heavy storm might reduce to-hit chances, force the PCs to take shelter, ruin unprotected food, etc.

Unusual events (Clear/d100):

1-10 Unusually hot
11-20 Unusually cold
21 Comet in sky, visible day and night
22 Comet in sky, visible night only
23-32 High winds (40+2d10 mph)
33-42 High winds (60+2d10 mph)
43-52 Becalmed
53-57 Meteor shower. 1% chance meteors land nearby.
58-59 New star appears in sky for 1-3 one night, 4-5 one fortnight, 6 permanent
60-61 Notable star disappears from sky for 1-3 one night. 4-5 one fortnight, 6 permanent
62-63 Sky turns unusual color for 1d4 hours
64-67 Partial solar eclipse
68-69 Total solar eclipse
70-75 Partial Lunar eclipse
76-77 Total lunar eclipse
78-79 Unusual "rain" of 1 frogs, 2 snakes, 3 blood, 4 flowers, 5 locusts, 6 fish
80-89 Excessively humid (1-3) or dry (4-6)
90-95 Dust devils
96-00 Flash flood. Storms for 1d6 minutes, depositing 1" per minute

Unusual Weather (Cloudy)

1-10 Unusually hot
11-20 Unusually cold
21 Clouds form image of specific 1-2 monster 3-4 location 5 NPC 6 PC
22 Clouds spell out message in 1-3 known language 4-6 unknown language
23-32 High winds (40+2d10 mph)
33-42 High winds (60+2d10 mph)
43-52 Becalmed
53-57 Vile smell permeates the air
58-59 Castle visible amongst the clouds
60-61 Fog descends upon the land, lasting 1d4 hours
62-63 Sky turns unusual color for 1d4 hours
64-67 Semi-solid fog descends upon the land, reducing movement by 1-3 5', 4-5 10', 6 15'. Lasts 1d4 hours
68-69 Fog containing strange monsters descends upon the land. Lasts 1d4 hours, monsters vanish with fog.
70-75 Clouds are magically summoned 1-4 to bring rain 5-6 for a sinister purpose
76-77 Fog descends upon the land. All those outdoors are affected with a temporary minor effect (such as Attribute bonus/penalty, the ability to read thoughts, etc.)
78-79 Unusual "rain" of 1 frogs, 2 snakes, 3 blood, 4 flowers, 5 locusts, 6 fish
80-89 Excessively humid
90-95 The sun is obscured for 1d12 hour. It is as dark as dusk during the day.
96-00 Flash flood. Storms for 1d6 minutes, depositing 1" per minute

I just go to the NOAA Climate Archives, pick a location with geography analogous to the game setting, pick a random month several decades ago, and roll from there.

Eulalios wrote:I just go to the NOAA Climate Archives, pick a location with geography analogous to the game setting, pick a random month several decades ago, and roll from there.

Um, okay. I guess that works as well.

But this is D&D man!! Where would we be without tables!
Isn't there a whole section of IP law or something dedicated to them?*



*Question is not really looking for answers but thank you!

Ravendas has an amazing weather generator in his suite of self-created D&D programs:

https://www.dropbox.com/sh/ifeo68p5u7y2ils/qcZgtEVqg-