diff --git a/src/main/java/org/elasticsearch/common/rounding/TimeZoneRounding.java b/src/main/java/org/elasticsearch/common/rounding/TimeZoneRounding.java
index b2aec9f6776c5..87c639a434982 100644
--- a/src/main/java/org/elasticsearch/common/rounding/TimeZoneRounding.java
+++ b/src/main/java/org/elasticsearch/common/rounding/TimeZoneRounding.java
@@ -156,21 +156,21 @@ public byte id() {
 
         @Override
         public long roundKey(long utcMillis) {
-            long offset = preTz.getOffset(utcMillis);
-            long time = utcMillis + offset;
-            return field.roundFloor(time) - offset;
+            long local = preTz.convertUTCToLocal(utcMillis);
+            return preTz.convertLocalToUTC(field.roundFloor(local), true, utcMillis);
         }
 
         @Override
         public long valueForKey(long time) {
             // now apply post Tz
-            time = time + postTz.getOffset(time);
-            return time;
+            return postTz.convertUTCToLocal(time);
         }
 
         @Override
-        public long nextRoundingValue(long value) {
-            return durationField.add(value, 1);
+        public long nextRoundingValue(long time) {
+            long currentWithoutPostZone = postTz.convertLocalToUTC(time, true);
+            long nextWithoutPostZone = durationField.add(currentWithoutPostZone, 1);
+            return postTz.convertUTCToLocal(nextWithoutPostZone);
         }
 
         @Override
@@ -268,21 +268,22 @@ public byte id() {
 
         @Override
         public long roundKey(long utcMillis) {
-            long time = utcMillis + preTz.getOffset(utcMillis);
-            return field.roundFloor(time);
+            long local = preTz.convertUTCToLocal(utcMillis);
+            return field.roundFloor(local);
         }
 
         @Override
         public long valueForKey(long time) {
             // after rounding, since its day level (and above), its actually UTC!
             // now apply post Tz
-            time = time + postTz.getOffset(time);
-            return time;
+            return postTz.convertUTCToLocal(time);
         }
 
         @Override
-        public long nextRoundingValue(long value) {
-            return durationField.add(value, 1);
+        public long nextRoundingValue(long currentWithPostZone) {
+            long currentWithoutPostZone = postTz.convertLocalToUTC(currentWithPostZone, true);
+            long nextWithoutPostZone = durationField.add(currentWithoutPostZone, 1);
+            return postTz.convertUTCToLocal(nextWithoutPostZone);
         }
 
         @Override
@@ -375,7 +376,7 @@ public byte id() {
 
         @Override
         public long roundKey(long utcMillis) {
-            long time = utcMillis + preTz.getOffset(utcMillis);
+            long time = preTz.convertUTCToLocal(utcMillis);
             return Rounding.Interval.roundKey(time, interval);
         }
 
@@ -383,9 +384,9 @@ public long roundKey(long utcMillis) {
         public long valueForKey(long key) {
             long time = Rounding.Interval.roundValue(key, interval);
             // now, time is still in local, move it to UTC
-            time = time - preTz.getOffset(time);
+            time = preTz.convertLocalToUTC(time,  true);
             // now apply post Tz
-            time = time + postTz.getOffset(time);
+            time = postTz.convertUTCToLocal(time);
             return time;
         }
 
@@ -435,7 +436,7 @@ public byte id() {
 
         @Override
         public long roundKey(long utcMillis) {
-            long time = utcMillis + preTz.getOffset(utcMillis);
+            long time = preTz.convertUTCToLocal(utcMillis);
             return Rounding.Interval.roundKey(time, interval);
         }
 
@@ -444,7 +445,7 @@ public long valueForKey(long key) {
             long time = Rounding.Interval.roundValue(key, interval);
             // after rounding, since its day level (and above), its actually UTC!
             // now apply post Tz
-            time = time + postTz.getOffset(time);
+            time = postTz.convertUTCToLocal(time);
             return time;
         }
 
diff --git a/src/test/java/org/elasticsearch/search/aggregations/bucket/DateHistogramTests.java b/src/test/java/org/elasticsearch/search/aggregations/bucket/DateHistogramTests.java
index 58595403aaf69..574908f78310b 100644
--- a/src/test/java/org/elasticsearch/search/aggregations/bucket/DateHistogramTests.java
+++ b/src/test/java/org/elasticsearch/search/aggregations/bucket/DateHistogramTests.java
@@ -44,11 +44,13 @@
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
+import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
 
 import static org.elasticsearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.elasticsearch.index.query.QueryBuilders.matchAllQuery;
 import static org.elasticsearch.search.aggregations.AggregationBuilders.*;
+import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertAcked;
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertSearchResponse;
 import static org.hamcrest.Matchers.*;
 import static org.hamcrest.core.IsNull.notNullValue;
@@ -1204,7 +1206,7 @@ public void singleValueField_WithExtendedBounds() throws Exception {
 
     @Test
     public void singleValue_WithMultipleDateFormatsFromMapping() throws Exception {
-        
+
         String mappingJson = jsonBuilder().startObject().startObject("type").startObject("properties").startObject("date").field("type", "date").field("format", "dateOptionalTime||dd-MM-yyyy").endObject().endObject().endObject().endObject().string();
         prepareCreate("idx2").addMapping("type", mappingJson).execute().actionGet();
         IndexRequestBuilder[] reqs = new IndexRequestBuilder[5];
@@ -1263,6 +1265,44 @@ public void testIssue6965() {
         assertThat(bucket.getDocCount(), equalTo(3l));
     }
 
+    public void testDSTBoundaryIssue9491() throws InterruptedException, ExecutionException {
+        assertAcked(client().admin().indices().prepareCreate("test9491").addMapping("type", "d", "type=date").get());
+        indexRandom(true,
+                client().prepareIndex("test9491", "type").setSource("d", "2014-10-08T13:00:00Z"),
+                client().prepareIndex("test9491", "type").setSource("d", "2014-11-08T13:00:00Z"));
+        ensureSearchable("test9491");
+        SearchResponse response = client().prepareSearch("test9491")
+                .addAggregation(dateHistogram("histo").field("d").interval(DateHistogram.Interval.YEAR).preZone("Asia/Jerusalem")
+                .preZoneAdjustLargeInterval(true))
+                .execute().actionGet();
+        assertSearchResponse(response);
+        Histogram histo = response.getAggregations().get("histo");
+        assertThat(histo.getBuckets().size(), equalTo(1));
+        assertThat(histo.getBuckets().get(0).getKey(), equalTo("2013-12-31T22:00:00.000Z"));
+        assertThat(histo.getBuckets().get(0).getDocCount(), equalTo(2L));
+    }
+
+    public void testIssue7673() throws InterruptedException, ExecutionException {
+        assertAcked(client().admin().indices().prepareCreate("test7673").addMapping("type", "d", "type=date").get());
+        indexRandom(true,
+                client().prepareIndex("test7673", "type").setSource("d", "2013-07-01T00:00:00Z"),
+                client().prepareIndex("test7673", "type").setSource("d", "2013-09-01T00:00:00Z"));
+        ensureSearchable("test7673");
+        SearchResponse response = client().prepareSearch("test7673")
+                .addAggregation(dateHistogram("histo").field("d").interval(DateHistogram.Interval.MONTH).postZone("-02:00")
+                .minDocCount(0))
+                .execute().actionGet();
+        assertSearchResponse(response);
+        Histogram histo = response.getAggregations().get("histo");
+        assertThat(histo.getBuckets().size(), equalTo(3));
+        assertThat(histo.getBuckets().get(0).getKey(), equalTo("2013-06-30T22:00:00.000Z"));
+        assertThat(histo.getBuckets().get(0).getDocCount(), equalTo(1L));
+        assertThat(histo.getBuckets().get(1).getKey(), equalTo("2013-07-31T22:00:00.000Z"));
+        assertThat(histo.getBuckets().get(1).getDocCount(), equalTo(0L));
+        assertThat(histo.getBuckets().get(2).getKey(), equalTo("2013-08-31T22:00:00.000Z"));
+        assertThat(histo.getBuckets().get(2).getDocCount(), equalTo(1L));
+    }
+
     /**
      * see issue #9634, negative interval in date_histogram should raise exception
      */