Cities: Skylines II features different types of climates with various characteristics unique to each map. Climates are based on latitude and longitude resulting in differences in the length of day and amount of sunlight as well as other elements such as temperature range, amount of cloud coverage, and precipitation. Those parameters mean all maps will introduce different Climates with four distinct seasons.
Climates can be ground into three basic Climate types that act as a foundation for each map’s unique characteristics. Maps based on the Temperate Climate have distinct seasonal changes, moderate precipitation, and a wide temperature range, while maps with the Continental Climate type introduce significant annual variations in temperature. Lastly, we have the Polar regions which feature a short and cold summer and a long-lasting cold winter. You may recognize which category a map falls into based on its displayed temperature range, but as Climates are customized for each map, you will experience significant differences between maps that fall into the Continental group.
Weather
Weather is closely tied to the climate and represents the climate’s seasonal changes. Each map features unique weather which changes with the simulation. You can encounter various intensities of rainy weather, different cloud coverage, temperature changes, etc.
Temperature has an influence on how much electricity the city consumes. The city consumes the least electricity at temperatures between 18°C/64°F and 22°C/71°F. Above and below those temperatures the electricity consumption increases until it reaches 200% below -18°C/-0.4°F or above 58°C/136°F.
On sunny and warm weather citizens will seek Leisure in outdoors areas such as parks, while on rainy, snowy or cold weather citizens will seek Leisure in indoors areas in the form of shopping and entertainment.
On cloudy weather solar power plants produce 25% less electricity.
Months and seasons
Each month lasts a day and night cycle and each season lasts three months. The length of the day-night cycle is based on the map’s climate and current season with nights being longer during the winter. As the sun sets the building lights and street lights come on, lighting the way for citizens.
Seasons affect more than just the amount of sunlight in a day though. Depending on the Climate, temperature changes over the course of the whole year, as does the chance of rain and cloud coverage. During cold months snow falls and covers the ground of maps with Climates that include cold seasons. When there is snow, the Road Maintenance building’s snowplows take care of excess snow on the roads, keeping up the road condition to reduce the risk of accidents. The map’s location plays an important role when it comes to seasons as cities located in the southern hemisphere experience the seasons at opposite times of the year compared to the northern hemisphere.
Natural disasters
Beyond the normal weather phenomena, Cities: Skylines II includes natural disasters adding random events and challenging gameplay. Disasters can be switched on and off when starting a new game or loading an existing save. Disasters can affect your city in many ways, and while you can prepare for possible natural disasters with disaster control systems, they can’t be avoided completely. On the mild end of the spectrum, disasters might cause traffic accidents that lead to traffic jams, which can further affect your services’ ability to respond to the disaster. They cause damage to buildings and citizens directly hit by the disaster, which burdens healthcare, deathcare, and rescue services and causes disruptions to the companies or services housed in the affected buildings.
When a disaster happens citizens will try to get to shelters, which cannot be destroyed by disasters. If all shelters are full they will try to escape in the direction opposite of the disaster.
Natural disasters are logged into the Event Journal which can be found in the right side panel of the main UI. The journal includes past events in chronological order and information about what happened, when it happened, and what outcome the event had.
Forest fire
Forest fires can happen in all climates though the risk of a forest fire happening is affected by precipitation level and temperature, for example, dry weather has a higher risk of forest fires breaking out. A forest fire near buildings can spread to them causing building fires and wreaking havoc in the city. It is important to take care of forest fires to prevent harm to the city.
You can prepare for forest fires by placing Firewatch Towers on the map. They decrease forest fire probability and firefighters' response time within their range, limiting the fallout if a forest fire should happen. Fire trucks can extinguish a fire when it reaches the road network but placing a Firefighting Helicopter Depot in your city helps to put out the fire in places where fire trucks have no access.
Hail storm
When the weather is cold, but not freezing, there is a possibility of a hail storm occurring. Hail storms cause physical damage to buildings but do not destroy them. The damaged buildings need to be repaired after the storm and the money and resources for those repairs come from the residents taking away from means that would usually go to building upkeep and leveling. A Hail storm can also cause traffic accidents, which of course interrupts the traffic flow. The citizens don’t need to evacuate but they prefer staying indoors during a hail storm.
Tornado
The Tornado is the most extreme natural disaster included in Cities: Skylines II. It affects citizens, vehicles, and buildings and can cause serious damage to them as it moves through the city. The buildings can get damaged or even destroyed by the Tornado, citizens can get injured or die, and a lot of traffic accidents tend to happen in the area the Tornado hits.
The best way to prepare for extreme natural disasters is by placing Small and Large Emergency Shelters in your city so that they are easily reachable for citizens. The Early Disaster Warning System can spot approaching natural disasters and informs citizens earlier to go to the shelters in time to avoid the disaster. The citizens will run to the shelters and the large emergency shelters feature evacuation buses that are deployed at the same time as the evacuation order. The evacuation buses will plan their path based on population density, prioritizing schools, medical clinics, and hospitals.