diff --git a/integrations/api_user_heatmap_test.go b/integrations/api_user_heatmap_test.go
index 105d39e9a..a0f0552a1 100644
--- a/integrations/api_user_heatmap_test.go
+++ b/integrations/api_user_heatmap_test.go
@@ -26,7 +26,7 @@ func TestUserHeatmap(t *testing.T) {
 	var heatmap []*models.UserHeatmapData
 	DecodeJSON(t, resp, &heatmap)
 	var dummyheatmap []*models.UserHeatmapData
-	dummyheatmap = append(dummyheatmap, &models.UserHeatmapData{Timestamp: 1603152000, Contributions: 1})
+	dummyheatmap = append(dummyheatmap, &models.UserHeatmapData{Timestamp: 1603227600, Contributions: 1})
 
 	assert.Equal(t, dummyheatmap, heatmap)
 }
diff --git a/models/fixtures/action.yml b/models/fixtures/action.yml
index 14cfd9042..e3f3d2a97 100644
--- a/models/fixtures/action.yml
+++ b/models/fixtures/action.yml
@@ -32,3 +32,27 @@
   repo_id: 22
   is_private: true
   created_unix: 1603267920
+
+- id: 5
+  user_id: 10
+  op_type: 1 # create repo
+  act_user_id: 10
+  repo_id: 6
+  is_private: true
+  created_unix: 1603010100
+
+- id: 6
+  user_id: 10
+  op_type: 1 # create repo
+  act_user_id: 10
+  repo_id: 7
+  is_private: true
+  created_unix: 1603011300
+
+- id: 7
+  user_id: 10
+  op_type: 1 # create repo
+  act_user_id: 10
+  repo_id: 8
+  is_private: false
+  created_unix: 1603011540 # grouped with id:7
diff --git a/models/user_heatmap.go b/models/user_heatmap.go
index 0e2767212..306bd1819 100644
--- a/models/user_heatmap.go
+++ b/models/user_heatmap.go
@@ -32,17 +32,14 @@ func getUserHeatmapData(user *User, team *Team, doer *User) ([]*UserHeatmapData,
 		return hdata, nil
 	}
 
-	var groupBy string
+	// Group by 15 minute intervals which will allow the client to accurately shift the timestamp to their timezone.
+	// The interval is based on the fact that there are timezones such as UTC +5:30 and UTC +12:45.
+	groupBy := "created_unix / 900 * 900"
 	groupByName := "timestamp" // We need this extra case because mssql doesn't allow grouping by alias
 	switch {
-	case setting.Database.UseSQLite3:
-		groupBy = "strftime('%s', strftime('%Y-%m-%d', created_unix, 'unixepoch'))"
 	case setting.Database.UseMySQL:
-		groupBy = "UNIX_TIMESTAMP(DATE(FROM_UNIXTIME(created_unix)))"
-	case setting.Database.UsePostgreSQL:
-		groupBy = "extract(epoch from date_trunc('day', to_timestamp(created_unix)))"
+		groupBy = "created_unix DIV 900 * 900"
 	case setting.Database.UseMSSQL:
-		groupBy = "datediff(SECOND, '19700101', dateadd(DAY, 0, datediff(day, 0, dateadd(s, created_unix, '19700101'))))"
 		groupByName = groupBy
 	}
 
diff --git a/models/user_heatmap_test.go b/models/user_heatmap_test.go
index 31e78a19c..b2aaea649 100644
--- a/models/user_heatmap_test.go
+++ b/models/user_heatmap_test.go
@@ -19,12 +19,20 @@ func TestGetUserHeatmapDataByUser(t *testing.T) {
 		CountResult int
 		JSONResult  string
 	}{
-		{2, 2, 1, `[{"timestamp":1603152000,"contributions":1}]`}, // self looks at action in private repo
-		{2, 1, 1, `[{"timestamp":1603152000,"contributions":1}]`}, // admin looks at action in private repo
-		{2, 3, 0, `[]`}, // other user looks at action in private repo
-		{2, 0, 0, `[]`}, // nobody looks at action in private repo
-		{16, 15, 1, `[{"timestamp":1603238400,"contributions":1}]`}, // collaborator looks at action in private repo
-		{3, 3, 0, `[]`}, // no action action not performed by target user
+		// self looks at action in private repo
+		{2, 2, 1, `[{"timestamp":1603227600,"contributions":1}]`},
+		// admin looks at action in private repo
+		{2, 1, 1, `[{"timestamp":1603227600,"contributions":1}]`},
+		// other user looks at action in private repo
+		{2, 3, 0, `[]`},
+		// nobody looks at action in private repo
+		{2, 0, 0, `[]`},
+		// collaborator looks at action in private repo
+		{16, 15, 1, `[{"timestamp":1603267200,"contributions":1}]`},
+		// no action action not performed by target user
+		{3, 3, 0, `[]`},
+		// multiple actions performed with two grouped together
+		{10, 10, 3, `[{"timestamp":1603009800,"contributions":1},{"timestamp":1603010700,"contributions":2}]`},
 	}
 	// Prepare
 	assert.NoError(t, PrepareTestDatabase())
@@ -51,9 +59,13 @@ func TestGetUserHeatmapDataByUser(t *testing.T) {
 
 		// Get the heatmap and compare
 		heatmap, err := GetUserHeatmapDataByUser(user, doer)
+		var contributions int
+		for _, hm := range heatmap {
+			contributions += int(hm.Contributions)
+		}
 		assert.NoError(t, err)
-		assert.Len(t, heatmap, len(actions), "invalid action count: did the test data became too old?")
-		assert.Len(t, heatmap, tc.CountResult, fmt.Sprintf("testcase %d", i))
+		assert.Len(t, actions, contributions, "invalid action count: did the test data became too old?")
+		assert.Equal(t, tc.CountResult, contributions, fmt.Sprintf("testcase %d", i))
 
 		// Test JSON rendering
 		json := jsoniter.ConfigCompatibleWithStandardLibrary
diff --git a/web_src/js/features/heatmap.js b/web_src/js/features/heatmap.js
index d1cb43dde..07ecaee46 100644
--- a/web_src/js/features/heatmap.js
+++ b/web_src/js/features/heatmap.js
@@ -7,8 +7,15 @@ export default async function initHeatmap() {
   if (!el) return;
 
   try {
-    const values = JSON.parse(el.dataset.heatmapData).map(({contributions, timestamp}) => {
-      return {date: new Date(timestamp * 1000), count: contributions};
+    const heatmap = {};
+    JSON.parse(el.dataset.heatmapData).forEach(({contributions, timestamp}) => {
+      // Convert to user timezone and sum contributions by date
+      const dateStr = new Date(timestamp * 1000).toDateString();
+      heatmap[dateStr] = (heatmap[dateStr] || 0) + contributions;
+    });
+
+    const values = Object.keys(heatmap).map((v) => {
+      return {date: new Date(v), count: heatmap[v]};
     });
 
     const View = Vue.extend({