diff --git a/SleepLib/machine.cpp b/SleepLib/machine.cpp
index 697193cf..b8b37029 100644
--- a/SleepLib/machine.cpp
+++ b/SleepLib/machine.cpp
@@ -236,48 +236,50 @@ Day *Machine::AddSession(Session *s,Profile *p)
     QDateTime d1,d2=QDateTime::fromMSecsSinceEpoch(s->first());
 
     QDate date=d2.date();
-    date.addDays(-1);
 
-    //qint64 date=s->first()/86400000;
-    //date--; //=date.addDays(-1);
-    //date*=86400000;
+   // pref["NoonDateSplit"]=true;
 
-    const int hours_since_last_session=4;
-    const int hours_since_midnight=12;
+    if (pref["NoonDateSplit"].toBool()) {
+        if (d2.time().hour()<12) date.addDays(-1);
+    } else {
+        date.addDays(-1);
 
-    bool previous=false;
-    // Find what day session belongs to.
-    if (day.find(date)!=day.end()) {
-        // Previous day record exists...
+        const int hours_since_last_session=4;
+        const int hours_since_midnight=12;
 
-        // Calculate time since end of previous days last session
-        span=(s->first() - day[date]->last())/3600000.0;
+        bool previous=false;
+        // Find what day session belongs to.
+        if (day.find(date)!=day.end()) {
+            // Previous day record exists...
 
-        // less than n hours since last session yesterday?
-        if (span < hours_since_last_session) {
-            previous=true;
+            // Calculate time since end of previous days last session
+            span=(s->first() - day[date]->last())/3600000.0;
+
+            // less than n hours since last session yesterday?
+            if (span < hours_since_last_session) {
+                previous=true;
+            }
+        }
+
+        if (!previous) {
+            // Calculate Hours since midnight.
+            d1=d2;
+            d1.setTime(QTime(0,0,0));
+            float secsto=d1.secsTo(d2);
+            span=secsto/3600.0;
+
+            // Bedtime was late last night.
+            if (span < hours_since_midnight) {
+
+                previous=true;
+            }
+        }
+
+        if (!previous) {
+            // Revert to sessions original day.
+            date=date.addDays(1);
         }
     }
-
-    if (!previous) {
-        // Calculate Hours since midnight.
-        d1=d2;
-        d1.setTime(QTime(0,0,0));
-        float secsto=d1.secsTo(d2);
-        span=secsto/3600.0;
-
-        // Bedtime was late last night.
-        if (span < hours_since_midnight) {
-
-            previous=true;
-        }
-    }
-
-    if (!previous) {
-        // Revert to sessions original day.
-        date=date.addDays(1);
-    }
-
     sessionlist[s->session()]=s;
 
     if (!firstsession) {
@@ -287,6 +289,7 @@ Day *Machine::AddSession(Session *s,Profile *p)
         firstday=lastday=date;
         firstsession=false;
     }
+
     if (day.find(date)==day.end()) {
         //QString dstr=date.toString("yyyyMMdd");
         //qDebug("Adding Profile Day %s",dstr.toAscii().data());
diff --git a/mainwindow.cpp b/mainwindow.cpp
index 6b0a8799..c7e2c224 100644
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -56,6 +56,9 @@ MainWindow::MainWindow(QWidget *parent) :
     if (!pref.Exists("LinkGraphMovement")) pref["LinkGraphMovement"]=true;
     else ui->action_Link_Graphs->setChecked(pref["LinkGraphMovement"].toBool());
 
+    if (!pref.Exists("NoonDateSplit")) pref["NoonDateSplit"]=false;
+    else ui->action_Noon_Date_Split->setChecked(pref["NoonDateSplit"].toBool());
+
     if (!pref.Exists("fruitsalad")) pref["fruitsalad"]=true;
 
     if (!pref.Exists("UseAntiAliasing")) pref["UseAntiAliasing"]=false;
@@ -231,3 +234,8 @@ void MainWindow::on_actionUse_AntiAliasing_triggered(bool checked)
     if (daily) daily->RedrawGraphs();
 
 }
+
+void MainWindow::on_action_Noon_Date_Split_toggled(bool checked)
+{
+    pref["NoonDateSplit"]=checked;
+}
diff --git a/mainwindow.h b/mainwindow.h
index 94fd284d..968afcfc 100644
--- a/mainwindow.h
+++ b/mainwindow.h
@@ -60,6 +60,8 @@ private slots:
 
     void on_actionUse_AntiAliasing_triggered(bool checked);
 
+    void on_action_Noon_Date_Split_toggled(bool );
+
 private:
     Ui::MainWindow *ui;
     Daily * daily;
diff --git a/mainwindow.ui b/mainwindow.ui
index 41c53b49..2bdf72c4 100644
--- a/mainwindow.ui
+++ b/mainwindow.ui
@@ -561,6 +561,7 @@
     <addaction name="separator"/>
     <addaction name="actionUse_AntiAliasing"/>
     <addaction name="action_Link_Graphs"/>
+    <addaction name="action_Noon_Date_Split"/>
     <addaction name="separator"/>
     <addaction name="action_Fullscreen"/>
    </widget>
@@ -655,6 +656,14 @@
     <string>&amp;Fullscreen Toggle</string>
    </property>
   </action>
+  <action name="action_Noon_Date_Split">
+   <property name="checkable">
+    <bool>true</bool>
+   </property>
+   <property name="text">
+    <string>&amp;Noon Date Split</string>
+   </property>
+  </action>
  </widget>
  <customwidgets>
   <customwidget>