Weather

weather.toml holds the weather profiles, named by climate. Maps and regions pick one by name:

[[weather]]
name = "desert"
rain_chance = 1
snow_chance = 0
storm_chance = 0
snow_threshold = 0
min_temperature = 10
max_temperature = 30
cold_chance = 0
cold_temperature = 0
heat_chance = 80
heat_temperature = 35
rain_temperature_drop = 5
storm_temperature_drop = 10

Field	Meaning
name	The name maps and regions use.
rain_chance, snow_chance, storm_chance	Chance (%) of that weather in the next hour, checked storm first, then snow, then rain.
snow_threshold	No snow at this temperature or above.
min_temperature, max_temperature	The range of a normal day.
cold_chance, cold_temperature	Chance (%) of a cold day, between min_temperature and cold_temperature.
heat_chance, heat_temperature	Chance (%) of a hot day, between max_temperature and heat_temperature.
rain_temperature_drop, storm_temperature_drop	How much rain or a storm lowers the temperature.

The shipped profiles are none, desert, tropical, temperate, highland, stormy, mild, snowy, cool and rainy. none never changes the weather. none also covers regions without a weather field, such as the dungeons.

How the server uses them

Each profile has one weather at a time, shared by every region and map that uses it. Every game hour (60 game minutes: 5 real minutes with the default ultima.world.seconds_per_uo_minute of 5) the server rolls it again: a storm, else snow when the day is colder than snow_threshold, else rain, else dry; what falls has a density from 10 to 70 particles. Every 24 game hours it rolls the day’s temperature: a hot day, a cold day or a normal one, lowered by rain or a storm. The weather is not saved: a restart rolls it again.

A player sees the weather of its region’s profile, or of its map’s profile outside every region. Inside a building (a static more than 10 above its head) it stays dry. The server sends packet 0x65 when the player’s weather changes: at login, on a region change, and on a check every 5 seconds that catches walking in and out of buildings; it is also resent every minute and every game hour, because the client stops showing the weather a few minutes after the last packet, and after every season packet (0xBC), which stops the client’s weather. During a storm the player outside hears thunder now and then. Game masters read or force it with .weather.

Validation at startup

The server stops when:

• weather.toml does not exist or has no [[weather]] entries;
• a profile has no name, or a name is used twice (names are case-sensitive);
• a chance is outside 0 to 100;
• min_temperature is above max_temperature.

See also

• Data files overview: file locations, loading order and shared value formats.
• Check your changes: validate edited data before restarting.