Sample outdoor weather from the climate preset so people can freeze and the clock can show it.

Protocol v8 adds tenths of a °C and precipitation to the clock frame; warmth drains from insulation versus place temperature.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/HSchool.Simulation/School.cs

@@ -78,9 +78,12 @@ public sealed class School : IDisposable
     /// <summary>Country used to generate this school's people. Needed again on 1 September.</summary>
     public string? CountryId { get; private set; }
 
-    /// <summary>Climate preset rolled at birth. Phase 32 reads it; it cannot change on a live school.</summary>
+    /// <summary>Climate preset rolled at birth. Weather reads it; it cannot change on a live school.</summary>
     public string? ClimatePresetId { get; private set; }
 
+    /// <summary>Street temperature and precipitation last committed for the clock and warmth.</summary>
+    public OutdoorWeather Weather { get; private set; } = OutdoorWeather.None;
+
     /// <summary>Skill everyone generated for this school speaks natively.</summary>
     public string? NativeLanguage { get; private set; }
 
@@ -132,11 +135,12 @@ public sealed class School : IDisposable
         ClimatePresetId = climatePresetId;
         NativeLanguage = nativeLanguage;
         Applicants = applicants;
-        RosterSpawner.Spawn(World, roster);
+        RosterSpawner.Spawn(World, roster, Catalog);
         PlanDay = null;
         LastDecisionSlot = null;
         Plans.Clear();
         DecisionQueue.Clear();
+        SyncWeather(force: true);
     }
 
     public bool TryStartAction(string personId, string actionId)
@@ -208,6 +212,7 @@ public sealed class School : IDisposable
         PlanDay = null;
         LastDecisionSlot = null;
         NeedDecay.Apply(World, Catalog, (next.Value - before).TotalMinutes);
+        SyncWeather(force: true);
         return new SkipEmptyResult(SkipEmptyError.None, next.Value, peopleChanged);
     }
 
@@ -224,7 +229,7 @@ public sealed class School : IDisposable
         Roster = roster;
         Applicants = applicants;
         var snapshot = PresenceSystem.Capture(this);
-        RosterSpawner.Replace(World, roster);
+        RosterSpawner.Replace(World, roster, Catalog);
         PresenceSystem.Restore(this, snapshot);
         TimetableDirty = true;
     }
@@ -274,16 +279,50 @@ public sealed class School : IDisposable
             if (Catalog is not null)
             {
                 var below = PresenceSystem.BelowThreshold(this);
+                SyncWeather(force: false);
                 NeedDecay.Apply(World, Catalog, gameMinutes);
+                WarmthDecay.Apply(this, gameMinutes);
                 PresenceSystem.EnqueueNewlyUrgent(this, below);
                 PresenceSystem.DrainDecisions(this);
                 LessonLearningSystem.Apply(this, gameMinutes);
             }
         }
+        else
+        {
+            SyncWeather(force: false);
+        }
 
         return peopleChanged;
     }
 
+    /// <summary>
+    /// Recomputes the street from the preset, seed and current time. Commits when the clock
+    /// tenths or precipitation change, so warmth does not jitter every tick. A skip must force
+    /// the morning sample — yesterday's evening must not stick.
+    /// </summary>
+    public void SyncWeather(bool force)
+    {
+        ObjectDisposedException.ThrowIf(_disposed, this);
+        var next = EvaluateWeather();
+        if (force || next.Tenths != Weather.Tenths || next.Precipitation != Weather.Precipitation)
+        {
+            Weather = next;
+        }
+    }
+
+    private OutdoorWeather EvaluateWeather()
+    {
+        if (Catalog is null
+            || ClimatePresetId is null
+            || !Catalog.ClimatePresets.TryGetValue(ClimatePresetId, out var preset)
+            || preset.Abstract)
+        {
+            return OutdoorWeather.None;
+        }
+
+        return WeatherSampler.Sample(preset, PeopleSeed, Clock.Time);
+    }
+
     private bool TryYearlyIntake(DateTime before, DateTime after)
     {
         if (Roster is null || Catalog is null || CountryId is null)
@@ -301,7 +340,7 @@ public sealed class School : IDisposable
         if (changed)
         {
             var snapshot = PresenceSystem.Capture(this);
-            RosterSpawner.Replace(World, Roster);
+            RosterSpawner.Replace(World, Roster, Catalog);
             PresenceSystem.Restore(this, snapshot);
             TimetableDirty = true;
         }