Blindly wrote a command.

foundation-core/src/main/kotlin/cloud/kubelet/foundation/core/features/player/LocalWeatherCommand.kt

@@ -0,0 +1,50 @@
+package cloud.kubelet.foundation.core.features.player
+
+import org.bukkit.GameMode
+import org.bukkit.WeatherType
+import org.bukkit.command.Command
+import org.bukkit.command.CommandExecutor
+import org.bukkit.command.CommandSender
+import org.bukkit.command.TabCompleter
+import org.bukkit.entity.Player
+
+class LocalWeatherCommand : CommandExecutor, TabCompleter {
+  private val weatherTypes = WeatherType.values().associateBy { it.name.lowercase() }
+
+  override fun onCommand(
+    sender: CommandSender,
+    command: Command,
+    label: String,
+    args: Array<out String>
+  ): Boolean {
+    if (sender !is Player) {
+      sender.sendMessage("You are not a player.")
+      return true
+    }
+    if (args.size != 1) {
+      return false
+    }
+
+    val name = args[0].lowercase()
+    val weatherType = weatherTypes[name]
+    if (weatherType == null) {
+      sender.sendMessage("Not a valid weather type.")
+      return true
+    }
+
+    sender.setPlayerWeather(weatherType)
+    sender.sendMessage("Weather set to \"$name\"")
+
+    return true
+  }
+
+  override fun onTabComplete(
+    sender: CommandSender,
+    command: Command,
+    alias: String,
+    args: Array<out String>
+  ): List<String> = when {
+    args.isEmpty() -> weatherTypes.keys.toList()
+    else -> listOf()
+  }
+}

foundation-core/src/main/kotlin/cloud/kubelet/foundation/core/features/player/PlayerFeature.kt

@@ -9,5 +9,6 @@ class PlayerFeature : Feature() {
     registerCommandExecutor(listOf("creative", "c"), GamemodeCommand(GameMode.CREATIVE))
     registerCommandExecutor(listOf("adventure", "a"), GamemodeCommand(GameMode.ADVENTURE))
     registerCommandExecutor(listOf("spectator", "sp"), GamemodeCommand(GameMode.SPECTATOR))
+    registerCommandExecutor(listOf("localweather", "lw"), LocalWeatherCommand())
   }
 }

foundation-core/src/main/resources/plugin.yml

@@ -57,3 +57,6 @@ commands:
     description: Teleport to the spawn of the current world.
     usage: /spawn
     permission: foundation.command.spawn
+  localweather:
+    description: Set the player's local weather in the client.
+    usage: /localweather <type>