diff --git a/superset/assets/src/explore/components/controls/DateFilterControl.jsx b/superset/assets/src/explore/components/controls/DateFilterControl.jsx
index 9e07b99037cac..4d210c433c2f6 100644
--- a/superset/assets/src/explore/components/controls/DateFilterControl.jsx
+++ b/superset/assets/src/explore/components/controls/DateFilterControl.jsx
@@ -66,8 +66,15 @@ const COMMON_TIME_FRAMES = [
 const TIME_GRAIN_OPTIONS = ['seconds', 'minutes', 'hours', 'days', 'weeks', 'months', 'years'];
 
 const MOMENT_FORMAT = 'YYYY-MM-DD[T]HH:mm:ss';
-const DEFAULT_SINCE = moment().startOf('day').subtract(7, 'days').format(MOMENT_FORMAT);
-const DEFAULT_UNTIL = moment().startOf('day').format(MOMENT_FORMAT);
+const DEFAULT_SINCE = moment()
+  .utc()
+  .startOf('day')
+  .subtract(7, 'days')
+  .format(MOMENT_FORMAT);
+const DEFAULT_UNTIL = moment()
+  .utc()
+  .startOf('day')
+  .format(MOMENT_FORMAT);
 const SEPARATOR = ' : ';
 const FREEFORM_TOOLTIP = t(
   'Superset supports smart date parsing. Strings like `last sunday` or ' +
@@ -109,8 +116,12 @@ function getStateFromCommonTimeFrame(value) {
     tab: TABS.DEFAULTS,
     type: TYPES.DEFAULTS,
     common: value,
-    since: moment().startOf('day').subtract(1, units).format(MOMENT_FORMAT),
-    until: moment().startOf('day').format(MOMENT_FORMAT),
+    since: moment()
+      .utc()
+      .startOf('day')
+      .subtract(1, units)
+      .format(MOMENT_FORMAT),
+    until: moment().utc().startOf('day').format(MOMENT_FORMAT),
   };
 }
 
@@ -119,13 +130,15 @@ function getStateFromCustomRange(value) {
   let since;
   let until;
   if (rel === RELATIVE_TIME_OPTIONS.LAST) {
-    until = moment().startOf('day').format(MOMENT_FORMAT);
+    until = moment().utc().startOf('day').format(MOMENT_FORMAT);
     since = moment()
+      .utc()
       .startOf('day')
       .subtract(num, grain)
       .format(MOMENT_FORMAT);
   } else {
     until = moment()
+      .utc()
       .startOf('day')
       .add(num, grain)
       .format(MOMENT_FORMAT);
diff --git a/superset/assets/src/explore/controls.jsx b/superset/assets/src/explore/controls.jsx
index 19773bb411c6a..40e1233c78024 100644
--- a/superset/assets/src/explore/controls.jsx
+++ b/superset/assets/src/explore/controls.jsx
@@ -1026,6 +1026,14 @@ export const controls = {
     freeForm: true,
     label: t('Time range'),
     default: t('No filter'),
+    description: t(
+      'The time range for the visualization. All relative times, e.g. "Last month", ' +
+      '"Last 7 days", "now", etc. are evaluated on the server using the server\'s ' +
+      'local time (sans timezone). All tooltips and placeholder times are expressed ' +
+      'in UTC (sans timezone). The timestamps are then evaluated by the database ' +
+      'using the engine\'s local timezone. Note one can explicitly set the timezone ' +
+      'per the ISO 8601 format if specifying either the start and/or end time.',
+    ),
   },
 
   max_bubble_size: {
diff --git a/superset/config.py b/superset/config.py
index 9d53858e6769e..d0ba32716f66a 100644
--- a/superset/config.py
+++ b/superset/config.py
@@ -597,13 +597,7 @@ class CeleryConfig(object):
 # What is the Last N days relative in the time selector to:
 # 'today' means it is midnight (00:00:00) of today in the local timezone
 # 'now' means it is relative to the query issue time
-DEFAULT_RELATIVE_END_TIME = 'today'
-
-# Is epoch_s/epoch_ms datetime format supposed to be considered since UTC ?
-# If not, it is sassumed then the epoch_s/epoch_ms is seconds since 1/1/1970
-# localtime (in the tz where the superset webserver is running)
-IS_EPOCH_S_TRULY_UTC = False
-
+DEFAULT_RELATIVE_END_TIME = 'now'
 
 # set on IS_KNOX_SSO_ENABLED here ,because of unit test cases and rest KNOX varibales are defined in superset_config.py
 IS_KNOX_SSO_ENABLED = False
diff --git a/superset/connectors/sqla/models.py b/superset/connectors/sqla/models.py
index d3827f545adf2..18ff8cc15fd66 100644
--- a/superset/connectors/sqla/models.py
+++ b/superset/connectors/sqla/models.py
@@ -137,13 +137,12 @@ def datasource(self):
         return self.table
 
     def get_time_filter(self, start_dttm, end_dttm):
-        is_epoch_in_utc = config.get('IS_EPOCH_S_TRULY_UTC', False)
         col = self.get_sqla_col(label='__time')
         l = []  # noqa: E741
         if start_dttm:
-            l.append(col >= text(self.dttm_sql_literal(start_dttm, is_epoch_in_utc)))
+            l.append(col >= text(self.dttm_sql_literal(start_dttm)))
         if end_dttm:
-            l.append(col <= text(self.dttm_sql_literal(end_dttm, is_epoch_in_utc)))
+            l.append(col <= text(self.dttm_sql_literal(end_dttm)))
         return and_(*l)
 
     def get_timestamp_expression(self, time_grain):
@@ -174,7 +173,7 @@ def lookup_obj(lookup_column):
                 TableColumn.column_name == lookup_column.column_name).first()
         return import_datasource.import_simple_obj(db.session, i_column, lookup_obj)
 
-    def dttm_sql_literal(self, dttm, is_epoch_in_utc):
+    def dttm_sql_literal(self, dttm):
         """Convert datetime object to a SQL expression string
 
         If database_expression is empty, the internal dttm
@@ -187,11 +186,7 @@ def dttm_sql_literal(self, dttm, is_epoch_in_utc):
         if self.database_expression:
             return self.database_expression.format(dttm.strftime('%Y-%m-%d %H:%M:%S'))
         elif tf:
-            if is_epoch_in_utc:
-                seconds_since_epoch = dttm.timestamp()
-            else:
-                seconds_since_epoch = (dttm - datetime(1970, 1, 1)).total_seconds()
-            seconds_since_epoch = int(seconds_since_epoch)
+            seconds_since_epoch = int(dttm.timestamp())
             if tf == 'epoch_s':
                 return str(seconds_since_epoch)
             elif tf == 'epoch_ms':