--- a/net/minecraft/server/WorldData.java
+++ b/net/minecraft/server/WorldData.java
@@ -12,6 +12,11 @@
 import java.util.UUID;
 import java.util.Map.Entry;
 import javax.annotation.Nullable;
+// CraftBukkit start
+import org.bukkit.Bukkit;
+import org.bukkit.event.weather.ThunderChangeEvent;
+import org.bukkit.event.weather.WeatherChangeEvent;
+// CraftBukkit end
 
 public class WorldData {
 
@@ -70,6 +75,7 @@
     private boolean Y;
     private final GameRules Z;
     private final CustomFunctionCallbackTimerQueue<MinecraftServer> aa;
+    public WorldServer world; // CraftBukkit
 
     protected WorldData() {
         this.f = WorldType.NORMAL;
@@ -436,6 +442,7 @@
             nbttagcompound.setString("WanderingTraderId", this.W.toString());
         }
 
+        nbttagcompound.setString("Bukkit.Version", Bukkit.getName() + "/" + Bukkit.getVersion() + "/" + Bukkit.getBukkitVersion()); // CraftBukkit
     }
 
     public long getSeed() {
@@ -528,6 +535,20 @@
     }
 
     public void setThundering(boolean flag) {
+        // CraftBukkit start
+        if (this.thundering == flag) {
+            return;
+        }
+
+        org.bukkit.World world = Bukkit.getWorld(getName());
+        if (world != null) {
+            ThunderChangeEvent thunder = new ThunderChangeEvent(world, flag);
+            Bukkit.getServer().getPluginManager().callEvent(thunder);
+            if (thunder.isCancelled()) {
+                return;
+            }
+        }
+        // CraftBukkit end
         this.thundering = flag;
     }
 
@@ -544,6 +565,20 @@
     }
 
     public void setStorm(boolean flag) {
+        // CraftBukkit start
+        if (this.raining == flag) {
+            return;
+        }
+
+        org.bukkit.World world = Bukkit.getWorld(getName());
+        if (world != null) {
+            WeatherChangeEvent weather = new WeatherChangeEvent(world, flag);
+            Bukkit.getServer().getPluginManager().callEvent(weather);
+            if (weather.isCancelled()) {
+                return;
+            }
+        }
+        // CraftBukkit end
         this.raining = flag;
     }
 
@@ -693,6 +728,12 @@
 
     public void setDifficulty(EnumDifficulty enumdifficulty) {
         this.F = enumdifficulty;
+        // CraftBukkit start
+        PacketPlayOutServerDifficulty packet = new PacketPlayOutServerDifficulty(this.getDifficulty(), this.isDifficultyLocked());
+        for (EntityPlayer player : (java.util.List<EntityPlayer>) (java.util.List) world.getPlayers()) {
+            player.playerConnection.sendPacket(packet);
+        }
+        // CraftBukkit end
     }
 
     public boolean isDifficultyLocked() {
@@ -808,4 +849,12 @@
         this.X.add(s);
         this.Y |= flag;
     }
+
+    // CraftBukkit start - Check if the name stored in NBT is the correct one
+    public void checkName(String name) {
+        if (!this.levelName.equals(name)) {
+            this.levelName = name;
+        }
+    }
+    // CraftBukkit end
 }