Staying Warm Without Wasting Coal

The mechanic in plain English

Your base temperature moves toward the temperature of the tile where it sits.

Four things can keep it warm:

The tile: map zones become colder toward the Capitol. Captured cities heat their tiles.
The Alliance Furnace: heats every base inside its marked square.
Your personal Furnace: burns your Coal to heat only your base.
Recon Planes from allies: give temporary emergency heat.

The important threshold is -20°C. If you remain below it for five minutes, your base freezes. A frozen player cannot start rallies or teleport, which can remove them from a capture or battle at the worst possible time.

The simple temperature rule

Use the least Coal that keeps your base safely above -20°C.

Early in the season, Coal is also needed to unlock factories and raise resistance. Leaving personal overdrive on when there is no danger slows your growth.

Normal conditions

If your base is safely above -20°C, leave the personal Furnace off or on its lowest necessary setting.

Blizzard approaching

Check Season 2 → Cold Wave for the exact temperature and countdown.
Stay inside the Alliance Furnace square.
Enable automatic Furnace operation.
Enable automatic overdrive only if normal heat will not be enough.
Turn overdrive off after the wave.

Base approaching `-20°C`

Turn on overdrive.
Ask allies to send Recon Planes.
Move to a warmer tile if you can do so before freezing.

Base already frozen

Allies select the frozen base and use Break the Ice. Each attempt costs stamina.
Once the ice is removed, raise the base above -20°C with the personal Furnace, Alliance Furnace coverage, or Recon Planes.
Keep it above the threshold for five minutes so it does not freeze again.

Breaking the ice without adding heat is incomplete; the base can freeze again.

Recon Planes: what members actually do

Open Season 2 → Cold Wave → World Info → Warm Up to find alliance members in danger.

Select a cold base and send a plane.
A plane normally gives +2°C temporary heat.
A profession skill can raise the effect to +4°C.
Several allies can stack their planes on the same base.
Sending a plane costs Coal, so use it where it prevents a freeze or enables an urgent rally/teleport.

This is the practical meaning of the Recon Aircraft mechanic: alliance members can rescue a player whose own Furnace is not keeping up.

Personal Furnace versus Alliance Furnace

Personal Furnace

Uses your Coal.
Raises your own temperature.
Overdrive heats faster but consumes Coal much faster.
Upgrades increase Virus Resistance and maximum heat.

Alliance Furnace

Uses donated alliance Coal.
Heats the entire marked square.
Lets weaker members survive with less personal Coal.
Its location determines where the alliance can safely form its hive.
It becomes the objective in Beast Crisis and Rare Soil War.

Keep the square densely occupied. Members whose personal Furnaces cannot survive the forecast need the warmest inner spaces first.

When higher temperature is useful

Temperature is not only defensive. The temperature panel can show production, healing, morale, or combat bonuses after the base reaches the required heat threshold.

Tap the temperature display to see the exact bonus currently active. Do not run overdrive merely because the temperature number can go higher; use it only when the displayed benefit is worth the Coal cost.

Avoid overheating

At high temperature, the game displays an On Fire countdown before the base loses durability. The supplied cards place that threshold at 50°C; use the live warning because versions differ.

During a Cold Wave

Open World Info → Warm Up to find alliance bases that are approaching -20°C. Send Recon Planes to members who need enough heat to avoid freezing, and use Break the Ice on bases that have already frozen.

The objective is not maximum temperature. Keep members above the freeze threshold without burning the Coal needed for factory and Furnace growth.