diff --git a/src/datepicker/datepicker.js b/src/datepicker/datepicker.js
index f8cdf1279f..2755ef90f3 100644
--- a/src/datepicker/datepicker.js
+++ b/src/datepicker/datepicker.js
@@ -259,9 +259,11 @@ angular.module('ui.bootstrap.datepicker', ['ui.bootstrap.dateparser', 'ui.bootst
 
         if ( scope.showWeeks ) {
           scope.weekNumbers = [];
-          var weekNumber = getISO8601WeekNumber( scope.rows[0][0].date ),
-              numWeeks = scope.rows.length;
-          while( scope.weekNumbers.push(weekNumber++) < numWeeks ) {}
+          var numWeeks = scope.rows.length;
+          for (var r = 0; r < numWeeks; r++) {
+            // use date at middle of the row (3) instead of 0 to avoid problems when first day is Sunday
+            scope.weekNumbers.push(getISO8601WeekNumber(scope.rows[r][3].date));
+          }
         }
       };
 
diff --git a/src/datepicker/test/datepicker.spec.js b/src/datepicker/test/datepicker.spec.js
index 1eb14a434d..c6a86a2543 100644
--- a/src/datepicker/test/datepicker.spec.js
+++ b/src/datepicker/test/datepicker.spec.js
@@ -135,7 +135,7 @@ describe('datepicker directive', function () {
     });
 
     it('renders the week numbers based on ISO 8601', function() {
-      expect(getWeeks()).toEqual(['34', '35', '36', '37', '38', '39']);
+      expect(getWeeks()).toEqual(['35','36','37','38','39','40']);
     });
 
     it('value is correct', function() {