Isles of the Saharan Sea: The Weather...

Good Afternoon, All:

I just wanted to interrupt the posts on encounters temporarily to talk about the weather. The weather of the Isles of the Saharan Sea typically follows a tropical pattern, with a longer dry season and a shorter wet season roughly a third the length of the dry season. Major monsoons and frequent thunderstorms strike during the wet season, during which only the foolish attempt to sail. Islanders typically mark the passage of long periods of time in "monsoons", referring to the shorter wet season. This roughly corresponds to a year in the Outer World, as the size and intensity of the Eternal Sun cycles on an annual basis.

Islanders typically experience the following weather patterns of note:

1. Rainfall is quite heavy, particularly during the wet season. Even during the dry season, rain will frequently fall, but not nearly in the quantities experienced in the wet season.
2. When standing on the coast, breezes typically blow in from the sea during the wet season, and blow out from the land during the dry season.
3. The higher the elevation, the cooler the temperature and the greater the amount of precipitation.
4. An average of ten major tropical storms occur every year, and can include hurricanes and monsoons. Hurricanes have an average Travel Speed of 10, and typically lasts for 1d6+1 days.

The weather system described here is based, at least loosely, on the article "Weathering The Storms", which appeared in Dragon Magazine #137. The process is pretty straightforward, and is used to generate weather for a month at a time:

1. Roll a d20 on on the appropriate Temperature Table to determine the month's usual temperature. If something seems odd, then reroll or create an in-game reason for the result to exist.
2. Roll a d100 thirty times to determine how many days of rain occur in that month.
3. Arrange rain days to taste.
4. For each rain day (or group of rain days), determine the Rain Type. If you are determining this for a group of consecutive days, roll 1d4+2 instead of 1d6.
5. For each non-rain day, determine the Non-Rain Type.
6. Roll a d12 to determine Wind Direction as needed.

Table: Dry Season Temperatures

1d20	Desert	Mountains	Forest/Marsh/Aquatic	Hills/Plains
1	Cool	Cool	Warm	Warm
2-10	Hot	Warm	Hot	Hot
11-19	Hot	Hot	Hot	Very Hot
20	Very Hot	Very Hot	Very Hot	Extremely Hot
Rain	5%	40%	15%	10%

Table: Wet Season Temperatures

1d20	Desert	Mountains	Forest/Marsh/Aquatic	Hills/Plains
1	Cool	Cool	Warm	Warm
2-10	Warm	Cool	Hot	Hot
11-19	Warm	Warm	Hot	Very Hot
20	Hot	Hot	Very Hot	Extremely Hot
Rain	5%	40%	90%	85%

Table: Rain Type

1d6	Rain Type	Wind Speed
1	Drizzle	Light
2	Drizzle	Light
3	Steady Rain	Moderate
4	Steady Rain	Strong
5	Storm	Severe
6	Powerful Storm	Windstorm (20% chance of Hurricane)

Table: Non-Rain Type

1d6	Wind Speed
1	Light
2	Light
3	Light
4	Moderate
5	Strong
6	Severe

Table: Wind Direction

1d12	Wind Blows Toward...
1-2	North
3-5	Northeast
6-7	East
8	Southeast
9	South
10	Southwest
11	West
12	Northwest

As always, the above is subject to change once I implement it in-game. If it doesn't prove to work effectively, I'll just swap it out with some other approach, such as a Random Encounter table littered with weather effects in addition to monsters.

If you have any thoughts or suggestions you would like to make that might enhance this simple weather system, please feel free to share.

Enjoy,
Flynn