Seasons

The year has four seasons of 7 in-game days each: spring, summer, autumn and winter, a year of 28 days. A season lasts about 1.9 real hours. The game starts on the first day of spring. Each new season blends in from the last over its first day, so nothing jumps at once.

The seasons change the air, the snow, the ice and what grows, but never the land itself.

Temperature

Each climate shifts the air by a number of degrees per season, on top of the place’s own warmth (which comes from where it lies and how high it is) and the cold of the night. Underground the season does not reach. How the air becomes the temperature you feel is on survival.

Climate	Spring	Summer	Autumn	Winter
Temperate	0 °C	+6 °C	−2 °C	−8 °C
Arid	+2 °C	+9 °C	+1 °C	−6 °C
Cold	−3 °C	+5 °C	−7 °C	−16 °C
Wet	0 °C	+4 °C	−1 °C	−8 °C
Swamp	+1 °C	+3 °C	+1 °C	−2 °C
Volcanic	0 °C	+4 °C	0 °C	−5 °C
Alpine	−4 °C	+4 °C	−7 °C	−18 °C
Tropical	+1 °C	+2 °C	0 °C	−1 °C

Wetness

Each climate also has a wetness per season. Wetter seasons and climates get more weather fronts: tropical and swamp islands have a wet summer and autumn and a dry winter and spring.

Climate	Spring	Summer	Autumn	Winter
Temperate	55%	40%	65%	50%
Arid	15%	5%	15%	25%
Cold	40%	45%	50%	60%
Wet	75%	65%	80%	75%
Swamp	40%	90%	90%	35%
Volcanic	30%	25%	35%	40%
Alpine	50%	40%	55%	60%
Tropical	30%	85%	90%	25%

Snow

In winter, snow covers the ground on Temperate, Cold and Alpine islands wherever the winter air (the place plus the season, before the night) is 8 °C or colder. It lies in patches about 10 tiles across that grow together as it gets colder, and covers everything 10 °C below that. A warm spot never gets snow, so a mild home may stay green all winter.

• Standing on snow chills you.
• Snow slows you down and muffles your footsteps; see weather.
• Footprints show in snow and fade, faster while it snows.
• Snow on the ground holds pollution until the thaw.

Ice

On Cold and Alpine islands, shallow water freezes in winter where the winter air is below 0 °C. The ice grows out from the shore as the cold deepens. Deep water and marsh never freeze. Ice lets you walk where you would otherwise need a boat.

Thin ice

At the start and the end of winter the ice is thin. Sprinting on it, or carrying more than 25 kg, cracks it; stay on the cracked spot (or keep up the strain) for 0.6 s and it breaks. You fall in and are soaked through. The hole freezes over again after 2 in-game hours. Zombies and people running on thin ice break it too.

Forage and crops

Wild berry bushes and mushrooms regrow at a rate set by the season and the climate. The table shows how fast berries / mushrooms regrow compared with normal; “none” means nothing regrows (bushes stand bare).

Climate	Spring	Summer	Autumn	Winter
Temperate	1.25× / 1.25×	1.5× / 1.25×	0.75× / 2×	none / none
Arid	0.75× / 0.25×	0.5× / none	0.75× / 0.5×	none / none
Cold	0.75× / 0.75×	1.25× / 1×	0.5× / 1.5×	none / none
Wet	1.25× / 1.5×	1.5× / 1.5×	1× / 2.5×	none / 0.25×
Swamp	1× / 1.5×	1.25× / 2×	1× / 2.5×	0.5× / 0.75×
Volcanic	0.75× / 0.5×	1× / 0.75×	0.5× / 1×	none / none
Alpine	0.5× / 0.5×	1.25× / 1×	0.5× / 1.25×	none / none
Tropical	1× / 1×	1.5× / 1.75×	1.5× / 2×	0.75× / 0.5×

Planters at home grow at 100% in spring, 100% in summer, 75% in autumn, 0% in winter. In winter an outdoor planter grows only while it is warmed: a planter near a fire or indoors grows at 75% of the normal speed. See base building.