The plugin includes a full working calendar system with everything you'll need. It works just like in real life with weeks, days, months, years and time. Seasons will start on specific dates. The custom event system allows you to create your own events too. You could for example create an event on Christmas, new years eve or anything else.
The calendar system has an option to change the length of the day and night to whatever number of minutes you want. This can be different per month, which means summer can have long days and short nights and winter the opposite. Any amount of minutes is accepted, you could also make a Minecraft day 40 minutes or even 24 hours. The calendar system can be configured to follow the date and time of the real world. Check out Synchronizing on how to do this and also how you can synchronize the time of multiple worlds. If you want the calendar system to pause when no players are online make sure to check out TimePauser on SpigotMC as well.
The calendar system works just like real life. The same amount of days per month, same months and 365 days per year. The only difference is that instead of real days it uses Minecraft days. A Minecraft day is 20 minutes long, which means a full year will take around 5 days. You can of course change how long a year is by changing the number of days per month or increasing the length of each day. The number of months and their names can also be changed. The active season is always based on the current date. If you change the season by doing
/rs setyou'll also notice the date changing. The season will always change to the season that it should be at the current date. It can't be winter in June unless you change the season start dates. A time system is also included. It is a simple 24 hours clock based on the Minecraft time in your world. You may notice this time being slightly different than the time displayed by other plugins (EssentialsX for example), that is because RealisticSeasons time takes the different day and night lengths into account. The first half of a Minecraft day may take 7 minutes when using RealisticSeasons while the second half of the day takes 13 minutes. EssentialsX would display 12:00 after 7 minutes while it should really be around 10:00. Stick to using RealisticSeasons time as much as possible. There are multiple ways for your players to view the current season, date and time. The easiest way is running /season. It will display the current season, date, time, days until next season and active events. See the banner of this page. The messages can be translated and changed.
Another way is using PlaceHolderAPI. This is the most preferred way since it allows you to display it anywhere you want (scoreboard, boss bar, messages, tab, etc). Check out PlaceHolderAPI if you want to learn how to do this.
Server owners can create their own custom events that trigger every day, on certain weekdays or on specific dates (every year). The custom event runs any command you want or sends messages to your players. The event will also be visible on /season. You could for example create a new years eve event on 31 December each year that gives all players fireworks. Your imagination is your limit! Check out configuration if you want to learn more about this.