A cyclone is an in-game weather event that has a chance of occurring in Tier VII-X battles on certain maps. The forecast of a cyclone is heavy rainfall, powerful wind, and thunder. Players are notified of an inbound cyclone two minutes after the battle starts with the appearance of a cyclone-countdown in the user interface. At the end of the 5-minute countdown, the cyclone becomes active. When this occurs, the cyclone-countdown will change to an active cyclone-indicator. Cyclones affect gameplay by reducing spotting range and altering the spotting mechanics of ships and aircraft.
Cyclones were first added to the game in Update 0.5.5, only appearing in the map North. In Update 0.5.7, limits on the use of Hydroacoustic Search and Surveillance Radar consumables during a cyclone were removed. Prior to Update 0.5.9, cyclones randomly began four to ten minutes into a battle and remained active for another four to ten minutes. This was changed to the current duration in a later update.
An active cyclone affects the spotting range of all ships and aircraft in the battle. As the cyclone increases in intensity, spotting range is reduced in increments. If a ship or aircraft is not within spotting range, it will not be visible. As the cyclone dissipates, the maximum spotting range will be restored in increments. When the cyclone ends, the cyclone-indicator will disappear, and spotting mechanics will return to normal. spotting range is not affected by a cyclone prior to the cyclone countdown appearing, during the cyclone countdown, or after the cyclone ends.
A ship's spotting range is reduced in increments to 8 kilometers. Ships within the maximum spotting range will be visible to the player. Ships that are beyond the maximum spotting range but are spotted by allies will appear only on the mini-map.
For example, the default sea detectability range of Scharnhorst is 15.66 kilometers. If a cyclone reduces the maximum spotting range of ships to 12 kilometers, Scharnhorst will be visible to any ships within 12 kilometers.
While a ship is using radar, her spotting range is the maximum of her radar range and the cyclone-caused spotting range. For example, when the cylone-caused spotting range is 8 km, a Baltimore's spotting range is 10 km as long as her 10 km radar is active.
When a ship has launched a spotting aircraft or a fighter plane, she can also see the enemies spotted by the plane, even if the distance between the enemy and the ship is higher than the spotting range.
Spotting range is reduced in increments. At the peak of the cyclone, spotting range of aircraft is reduced to 8 kilometers. Aircraft will only be engaged by a ship's anti-aircraft armament when the squadrons are visible to the ship. As the cyclone dissipates, normal spotting range is slowly restored.
In affected battles, a cyclone-countdown is displayed two minutes after the battle starts. The cyclone countdown lasts for five minutes. The cyclone becomes active at the end of the countdown. The cyclone is active for a total of five to seven minutes before dissipating and ending. A cyclone may only appear once in a match.
There is a 10% chance of a cyclone occurring in Tier VII-X battles on the following maps:
- The Atlantic
- Land of Fire
- Mountain Range
- Sea of Fortune
- Two Brothers
- Warrior‘s path
There is a chance of a cyclone occurring in the following Scenarios:
During a cyclone, it is important to watch the mini-map. Ships and aircraft may be detected but not yet visible, because they are outside the maximum spotting range. Determining the enemy's direction and movement is key to carrying out or avoiding an engagement. Seeing incoming aircraft may allow for effective use of the Defensive AA Fire consumable. Consumables such as Hydroacoustic Search and Surveillance Radar are extremely useful tools that can be used to detect nearby ships.
Reduced spotting range allows for a ship to more easily attack a flank and push into a capture point or base without being spotted. However, be mindful of the cyclone's duration and have a plan for when it ends.