diff --git a/lib/cartodb/models/dataview/histograms/date-histogram.js b/lib/cartodb/models/dataview/histograms/date-histogram.js
index 064de0ae..6060dbac 100644
--- a/lib/cartodb/models/dataview/histograms/date-histogram.js
+++ b/lib/cartodb/models/dataview/histograms/date-histogram.js
@@ -245,8 +245,8 @@ module.exports = class DateHistogram extends HistogramBase {
                         return closer;
                     }
 
-                    var closerDiff = MAX_INTERVAL_VALUE - closer.value;
-                    var currentDiff = MAX_INTERVAL_VALUE - current.value;
+                    const closerDiff = MAX_INTERVAL_VALUE - closer.value;
+                    const currentDiff = MAX_INTERVAL_VALUE - current.value;
 
                     if (Number.isFinite(current.value) && closerDiff > currentDiff) {
                         return current;
@@ -332,7 +332,7 @@ module.exports = class DateHistogram extends HistogramBase {
     }
 
     _populateBinStart (override, firstRow) {
-        var binStart;
+        let binStart;
 
         if (firstRow.hasOwnProperty('timestamp')) {
             binStart = firstRow.timestamp;