diff --git a/sleepyhead/Graphs/gGraphView.cpp b/sleepyhead/Graphs/gGraphView.cpp
index 8bbf7448..f9ded175 100644
--- a/sleepyhead/Graphs/gGraphView.cpp
+++ b/sleepyhead/Graphs/gGraphView.cpp
@@ -1385,6 +1385,14 @@ void gGraphView::paintGL()
 
 QString gGraphView::getRangeString()
 {
+    // a note about time zone usage here
+    // even though this string will be displayed to the user
+    // the graph is drawn using UTC times, so no conversion
+    // is needed to format the date and time for the user
+    // i.e. if the graph says the cursor is at 5pm, then that
+    // is what we should display.
+    // passing in UTC below is necessary to prevent QT
+    // from automatically converting the time to local time
     QString fmt;
 
     qint64 diff = m_maxx - m_minx;
diff --git a/sleepyhead/overview.cpp b/sleepyhead/overview.cpp
index 172e4d33..82b80f67 100644
--- a/sleepyhead/overview.cpp
+++ b/sleepyhead/overview.cpp
@@ -475,7 +475,10 @@ gGraph *Overview::createGraph(QString code, QString name, QString units, YTicker
 void Overview::on_LineCursorUpdate(double time)
 {
     if (time > 1) {
-        QDateTime dt = QDateTime::fromMSecsSinceEpoch(time,Qt::UTC);
+        // even though the generated string is displayed to the user
+        // no time zone conversion is neccessary, so pass UTC
+        // to prevent QT from automatically converting to local time
+        QDateTime dt = QDateTime::fromMSecsSinceEpoch(time, Qt::UTC);
         QString txt = dt.toString("dd MMM yyyy (dddd)");
         dateLabel->setText(txt);
     } else dateLabel->setText(QString(GraphView->emptyText()));