How Temperature Works
Temperature follows a smooth cosine wave across the year — rising from the spring baseline to a summer peak, then falling through an autumn baseline into the winter trough. The same shape every year, with small random shifts from weather events. There are no surprise flash-freezes; winters are cold because they're always cold.
The three climate presets set how high the summer peak goes and how low the winter trough falls. The spring and autumn baseline is the same for all three — roughly cool and comfortable. The gap between the presets is the swing.
The Three Climates
| Climate | Summer peak | Winter trough | Notes |
|---|---|---|---|
| Mild | +18 °C / 64 °F | −3 °C / 27 °F | Winters are barely below freezing. Warmth is rarely a crisis. Warm-season crops (coffee beans, corn) may underperform. |
| Fair | +25 °C / 77 °F | −10 °C / 14 °F | Default. A meaningful winter that requires fuel and warm clothes, but manageable from early on. |
| Harsh | +35 °C / 95 °F | −20 °C / −4 °F | Deep winters that demand serious preparation. Fuel shortages in winter are life-threatening. Hot summers open up tropical crops. |
Climate is chosen independently of map type. A Highlands map can be Mild; a Valley can be Harsh. The two settings don't interact except through gameplay consequences.
Effect on Warmth
Temperature drives the warmth need directly. When it's cold, the warmth need decays faster — citizens burn through it more quickly and must be in a fuelled home or near the Great Hearth to restore it. There's a comfortable baseline temperature around which the decay rate is normal; above it, warmth decays a little slower; below it, faster and faster as temperature drops.
On a Harsh winter at −20 °C (−4 °F), warmth is a serious concern for every citizen every season. On Mild at −3 °C (27 °F), a few citizens in poorly-fuelled homes might get uncomfortable, but it rarely becomes a crisis.
See the Fuel & Heating guide for how homes burn fuel and restore warmth.
Effect on Crops
Every crop has a temperature range — a minimum and a maximum it can tolerate at harvest. If the temperature at harvest time falls outside that range, the crop produces nothing. This is visible in the Farming Calendar (press F8), which colour-codes each crop by whether it works on your current map.
| Climate | Crop considerations |
|---|---|
| Mild | Cold-hardy crops (rye, turnips, carrots, onions) are reliable year-round. Warm-season crops like coffee beans and corn may fail to meet their minimum temperature in summer and produce nothing or reduced yields. Check the calendar before committing fields. |
| Fair | A full range of crops is viable. Summer crops grow and autumn crops harvest without issue. The default experience the game is balanced around. |
| Harsh | The hot summer unlocks crops with high temperature minimums (coffee beans thrive). The deep winter means cold-hardy crops are especially valuable for the autumn harvest window before temperatures plunge. Frost-tolerant crops (carrots, turnips, onions) become more strategically important as insurance. |
Difficulty and Climate
The difficulty setting multiplies the size of the seasonal temperature swing. This stacks on top of the climate preset — choose both carefully.
| Difficulty | Temperature swing | Effect |
|---|---|---|
| Easy | 75% of preset | The swing from summer to winter is smaller. Winters are less cold; summers are less hot. |
| Medium | 100% of preset | The climate plays exactly as the preset describes. |
| Hard | 125% of preset | The swing is amplified. Winters are colder than the preset; summers are hotter. |
The combination of Harsh + Hard produces the most punishing winters in the game — well below −20 °C (−4 °F) — and is intended for experienced players who want a genuine survival challenge. Mild + Easy effectively removes winter as a threat, letting you focus on other systems without warmth management pressure.