Weather, day and night: sun, moon and storms

How long is a day?

• 25 minone full day and night
• 29.5 daysfrom one new Moon to the next (about 12 hours of real time)
• 365 daysone year (about 6 real days)

The planet turns once every 1,500 seconds. The time of day depends on where you stand: when it is noon where you are, it is night on the other side of the planet. The axis is tilted by 23.44 degrees, so the poles have polar days and polar nights. The Sun and the Moon are on real orbits, so the Moon rises, sets, waxes and wanes. When the sky goes dark, monsters come (see your first night and night monsters).

Can I change the time and the weather?

On a server with roles, /settime and /time add need a permission, which the admin role has by default. /weather and /weather forecast are for everyone.

/settime noon
/time add 6
/weather forecast

What kinds of weather are there?

• Weather systems. Lows and highs about 350 km wide drift with the winds of their latitude: the trade winds blow west near the equator, the westerlies east between 30 and 60 degrees, the polar winds west again near the poles. Systems form and fade over a couple of days; inside them rain bands and storm cells 10 to 40 km wide come and go, and finer fronts a few kilometres wide pass over you. Where you stand, a weather usually lasts 5 to 20 minutes. The same seed and the same time always give the same weather, everywhere on the planet, even where nobody is.
• Zones. The equator is wet and stormy, the dry belts around 20 to 35 degrees are sunny (the deserts), the middle latitudes from 40 to 60 degrees are wet and windy, and the poles are cold and dry. Thunderstorms like hot afternoons, fog the end of the night and cold water.
• Snow falls on cold land (taiga, tundra, peaks). It becomes a blizzard when the fall is heavy and the wind is over 11 m/s.
• Rain falls on temperate and hot land, and heavy rain on warm land turns into a thunderstorm.
• Deserts get only a few drops. When the wind blows over 12 m/s, they get a sandstorm.
• Fog settles on humid land when the wind is light.
• Wind is calm near the equator, steady in the trade winds and strong in the storm belt of the middle latitudes; it is stronger over the open sea, over dry bare ground, on summits and under storms.
• Air. The air is warm by day and cooler at night, colder under rain, snow and fog, a little colder during a solar eclipse. Its mean comes from the place: hot deserts, cold peaks and poles.

What does the weather do?

• The sky greys over, a cloud layer at 720 m drifts with the wind, rain and snow fall, and fog closes the view. Sand and blizzard shut it down to about 50 m.
• The ground gets wet: soaked in about 70 s of heavy rain, with puddles, and dry again in about 15 min. Snow whitens the ground in about 3 min of heavy snow, and melts when it is warm.
• It only happens where the sky is open: never in a cave, under a roof or under a tree.
• A thunderstorm throws real bolts of lightning, 25 to 320 m from you. The sky and the ground flash, and for now the lightning does no damage.
• Weather quality is a setting under Display: minimal, low, medium (the default) or high.

Are there seasons?

The year is real in the sky: 365 days of 25 minutes, which is about 6 days of real time, with the axis tilted 23.44 degrees. But the weather has no season calendar: it comes from the place (its latitude, climate and height) and from the drifting weather systems, not from the date.

What about eclipses?

In Openworld the Moon's orbit is tilted by only 0.5 degrees, so every lunar month brings a solar eclipse and a lunar eclipse. An eclipse hides the disc of the Sun and drops the ambient light, so the world really darkens. The eclipse guide explains the geometry.

Updated 2026-10-20